Tri-Star Petroleum Company v Australia Pacific LNG Pty Ltd

PROCEDURE - SUPREME COURT PROCEDURE - QUEENSLAND - PLEADINGS - STRIKING OUT - where an application is made under r 171(1)(a) of the Uniform Civil Procedure Rules 1999 (Qld) - where representations and assumptions are said to be untenable and incapable of success - where defects in the pleading of detrimental reliance, loss and causation are alleged - where claims in unjust enrichment and estoppel by convention are also challenged - where miscellaneous paragraphs are said to disclose no reasonable cause of action - whether the impugned pleading should be struck out

ESTOPPEL - ESTOPPEL IN PAIS - EQUITABLE ESTOPPEL - REPRESENTATIONS - SILENCE - where representations are alleged to arise from silence or conduct - where it is contended that no duty to disclose reversion existed - where the alleged conduct is said not to be inconsistent with reversion having occurred - where the alleged representations are said to amount only to expressions of opinion - whether the pleaded facts are capable of constituting representations

TRADE PRACTICES - MISLEADING OR DECEPTIVE CONDUCT - REPRESENTATIONS - SILENCE - where representations by silence are alleged to the effect that reversion would not be asserted - where it is contended that the pleading discloses no such representation - where allegations concerning the absence of reasonable grounds are said to be irrelevant - whether the pleading discloses a viable claim of misleading or deceptive conduct

ESTOPPEL - PROPRIETARY ESTOPPEL - STANDING BY - KNOWLEDGE - where proprietary estoppel by standing by is alleged - where it is contended that the requisite knowledge to found such an estoppel was absent - where correspondence is said to have notified the opposing party of the position regarding inclusion of the CP payment in reversion calculations - where any alleged standing by is said to have ceased upon that notification - whether the plea of proprietary estoppel by standing by is untenable

183 Eastwood Pty Ltd v Dragon Property Development & Investment Pty Ltd [2023] NSWCA 72

AFSL v Hills Industries (2014) 253 CLR 560

Agar v Hyde [2000] HCA 41; (2000) 201 CLR 552

Amalgamated Investment & Property Company Ltd (In Liq) v Texas Commerce International Bank Ltd [1982] QB 84

Amcor Limited v Peter James Ramsay [2018] VSC 75

Australian Breeders Co-operative Society Ltd v Jones [1997] FCA 1405; (1997) 150 ALR 488

Barclay Mowlem Construction Limited v Dampier Port Authority [2006] WASC 281; (2006) 33 WAR 82

Barport Pty Ltd v Baum [2019] VSCA 167

Batistatos v Roads and Traffic Authority (NSW) [2006] HCA 27; (2006) 226 CLR 256

Bell Group Ltd (in liq) v Westpac [2008] WASC 239; (2009) 39 WAR 1

Bluehaven Enterprises Ltd v Tully [2006] 4 LRC 658

Butcher v Lachlan Elder Realty Pty Limited [2004] HCA 60; (2004) 218 CLR 592

Campbell v Backoffice Investments Pty Ltd (2009) 238 CLR 304

Combe v Combe [1952] EWCA Civ 7; [1951] 2 KB 215

David Securities Pty Ltd v Commonwealth Bank of Australia [1992] HCA 48; (1992) 175 CLR 353

Delaforce v Simpson-Cook [2010] NSWCA 84; (2010) 78 NSWLR 483

Densom v Cootamundra Racecourse Trust [2000] NSWSC 1072

Digi-Tech (Aust) Ltd v Brand [2004] NSWCA 58

E Co v Q [2018] NSWSC 442

Ecosse Property Holdings Pty Ltd v Gee Dee Nominees Pty Ltd [2017] HCA 12; (2017) 261 CLR 544

Equititrust Limited (Receivers and Managers Appointed) v Tucker [2019] QSC 248

Eslea Holdings Ltd v Butts (1986) 6 NSWLR 175

Garner v Central Innovation Pty Ltd [2022] FCAFC 64

General Steel Industries Inc v Commissioner for Railways (NSW) [1964] HCA 69; (1964) 112 CLR 125

Grundt v Great Boulder Pty Gold Mines Ltd [1937] HCA 58; (1937) 59 CLR 641

Haven Pty Ltd v Webster [2005] NSWCA 182

I & L Securities v HTW Valuers (Brisbane) Pty Ltd [2002] HCA 41; (2002) 210 CLR 109

Impiombato v BHP Group Limited (No. 2) [2020] FCA 1720

Kammins Ballrooms Co Ltd v Zenith Investments [1971] AC 850

Kramer v Stone [2024] HCA 48; (2024) 281 CLR 484

Legione v Hateley [1983] HCA 11; (1983) 152 CLR 406

Low v Bouverie [1891] 3 Ch 82

Middleton v Aon Risk Services Australia Ltd [2008] WASCA 239

Miller & Associates Insurance Broking Pty Ltd v BMW Australia Finance Limited [2010] HCA 31; (2010) 241 CLR 357

Moorgate Mercantile Credit Co Ltd v Twitchings [1977] AC 890

Newbon v City Mutual Life Assurance Society Ltd [1935] HCA 33; (1935) 52 CLR 723

Orion Finance Ltd v J D Williams & Company Ltd [1997] EWCA Civ 1

Pegella Pty Ltd v National Mutual Life Association of Australasia Ltd [2006] VSC 507

Polar Aviation Pty Limited v Civil Aviation Safety Authority (No.4) [2011] FCA 1126; (2011) 203 FCR 293

Priestley v Priestley [2016] NSWSC 1096

Priestley v Priestley [2017] NSWCA 155

Prudential Assurance Co Ltd v Newman Industries Ltd (No 2) [1982] Ch 204

Q v E [2020] NSWCA 220; (2020) 383 ALR 469

Ramsden v Dyson (1866) LR 1 HL 129

Salib v Gakas [2010] NSWSC 505

Sedgwick Australia Pty Ltd v JLOC Super Pty Ltd [2024] QCA 218

Sellars v Adelaide Petroleum NL [1994] HCA 4; (1994) 179 CLR 332

Sidhu v Van Dyke (2014) 251 CLR 505

Sloan v Arnold Thomas & Becker Pty Ltd [2019] VSC 292

Spencer v The Commonwealth (2010) HCA 28; (2010) 241 CLR 118

Streeter v Western Areas Exploration Pty Ltd (No. 2) [2011] WASCA 17; (2011) 278 ALR 291

Taylors Fashions Ltd v Liverpool Trustees Co [1982] 1 QB 133

Thompson v Palmer [1933] HCA 61; (1933) 49 CLR 507

Tradax Export SA v Dorada Compania Navierasa [1982] 2 Lloyd's REP 140

Tri-Star Petroleum Company v Australia Pacific LNG Pty Ltd (formerly Oil Company of Australia Limited) [2023] QSC 83

Uber Australia Pty Ltd v Andrianakis [2020] VSCA 186

Waltons Stores (Interstate) Ltd v Maher [1988] HCA 7; (1988) 164 CLR 387

Williams & Humbert v W & H Trade Marks [1986] 1 AC 368

Willmott v Barber (1880) 15 Ch D 96

For the applicant: S Couper KC, J O'Regan and T Pagliano

For the respondent: RC Higgins SC, S Webster KC, BJ Kable and BJ Fernandez

[1] The plaintiffs ("Tri-Star") have applied to strike out various paragraphs of the sixth further amended defence and counterclaim ("the pleading"). The application is made in reliance on r 171 of the Uniform Civil Procedure Rules 1999 (Qld) ("the UCPR") and the inherent jurisdiction of the Court. Tri-Star makes no application for summary judgment.

[2] Since in or about October 2014, Tri-Star and the defendants ("APLNG") have been parties to this proceeding, which has been described as involving "a complex and lengthy" set of circumstances[1] concerned with rights, obligations and ownership interests relating to coal seam gas tenements. In late 2008, ConocoPhillips paid the first defendant, Australia Pacific LNG Pty Ltd, the sum of $7,562,688,343.00 to subscribe for 100 million ordinary shares in the first defendant ("the CP payment"). An issue of primary importance in the proceeding is whether, by reason of the CP payment, 45% of various interests previously sold to the first defendant reverted to Tri-Star. The present application is not concerned with the resolution of that issue, which depends on the proper construction of a Sale and Purchase Deed dated 14 February 2002 ("the 2002 Deed"). As to remedies, Tri-Star seeks declaratory and injunctive orders about the alleged reversion along with damages for breach of contract, equitable compensation or an account of profits for the alleged sale of its gas since the reversion. By the pleading, APLNG counterclaims, inter alia, for declarations as to the proper construction of the 2002 Deed, declarations that Tri-Star is estopped from contending that reversion occurred by reason of the CP payment and damages pursuant to s 82 of the Trade Practices Act 1974 (Cth) and equivalent provisions in the Competition and Consumer Act 2010 (Cth).

[3] In General Steel Industries Inc v Commissioner for Railways (NSW),[2] when discussing the jurisdiction, whether statutory or inherent, to summarily terminate a proceeding, Barwick CJ noted that its exercise should not be reserved for those cases where argument is unnecessary to evoke the futility of a plaintiff's claim. In that context, Barwick CJ observed that "[a]rgument perhaps even of an extensive kind may be necessary to demonstrate that the case of the plaintiff is so clearly untenable that it cannot possibly succeed".[3] In Williams & Humbert v W & H Trade Marks (Jersey) Ltd,[4] in the context of a strike out application, Lord Templeman described a "general rule" to the effect that "the judge should ... decline to proceed with the argument unless he not only harbours doubts about the soundness of the pleading but, in addition, is satisfied that striking out will obviate the necessity for a trial or will substantially reduce the burden of preparing for trial or the burden of the trial itself". Any such general rule is not inflexible, as the decision on the facts of Williams & Humbert makes clear.[5] Further, any such general rule as referred to in Williams & Humbert would now fall to be considered against the background of the philosophy enshrined by r 5 and the content of the pleading rules contained within the UCPR. In the context of the UCPR, and the modern case management of complex cases such as the present case, the proper approach is to the effect that "only where the criticisms of a pleading significantly impact upon the proper presentation of the case and its presentation at trial, should those criticisms be seriously entertained".[6] In this case, the complexity of the pleading meant that extensive argument was inevitably necessary to reveal whether it was sound or otherwise and its likely impact on the preparation and conduct of the trial.

[4] The present application gave rise to written submissions of considerable length and oral submissions spanning two days. The application was not advanced on the basis that success would lead to the summary termination of the proceeding. Although in one context, APLNG described Tri-Star's contentions as "technical pleading complaints",[7] APLNG otherwise emphasised that Tri-Star's submissions were framed in terms that various parts of the pleading were amenable to striking out because they were variously "untenable,"[8] "hopeless"[9] or an "abuse of process".[10] Tri-Star also submitted that the pleading did not "disclose a reasonable cause of action,"[11] or revealed causes of action which "must fail,"[12] "cannot succeed,"[13] had "no material prospect of success"[14] or "no reasonable prospect" of success.[15] Properly characterised, Tri-Star's substantive complaints were to the effect that relevant parts of the pleading did not disclose an arguable defence or cause of action or were an abuse of process. Characterised in that way, and properly analysed, the complaints, if vindicated, were of a nature which were likely to impact the proper preparation of the proceeding, the presentation of the parties' respective cases at trial and the burden of preparing for the trial. That characterisation required the court to seriously entertain the parties' arguments.[16]

[5] The power to strike-out a pleading on the basis that it fails to disclose a reasonable cause of action, "must be exercised with caution and should only be exercised in the plain and obvious case".[17] The case law acknowledges that common experience teaches that it is usually more efficient and just to consider the viability of a cause of action when the facts said to support it are adduced and the suggested action can be judged with a full understanding of all relevant evidence.[18] It may be observed that several of Tri-Star's submissions sought to raise and dispose of a variety of questions of law and fact on the basis that those questions could, and should, be summarily decided without a trial. The approach to summary determination is settled.[19] In Batistatos v Roads and Traffic Authority (NSW)[20], the plurality[21] repeated an earlier statement in Agar v Hyde[22] in the following terms:

"Ordinarily, a party is not to be denied the opportunity to place his or her case before the court in the ordinary way, and after taking advantage of the usual interlocutory processes. The test to be applied has been expressed in various ways, but all of the verbal formulae which have been used are intended to describe a high degree of certainty about the ultimate outcome of the proceeding if it were allowed to go to trial in the ordinary way"

[6] In Spencer v The Commonwealth,[23] the High Court considered s 31A(2) of the Federal Court of Australia Act 1976 (Cth) which deals with summary judgment and the requirement for a court to be satisfied that a party has no reasonable prospect of success. In the context of considering that summary judgment test, which is not applicable to this strike out application, French CJ and Gummow J made theses pertinent observations about summary dismissal:

"Where there are factual issues capable of being disputed and in dispute, summary dismissal should not be awarded to the respondent simply because the Court has formed the view that the applicant is unlikely to succeed on the factual issue. Where the success of a proceeding depends upon propositions of law apparently precluded by existing authority, that may not always be the end of the matter. Existing authority may be overruled, qualified or further explained. Summary processes must not be used to stultify the development of the law."

[7] In Uber Australia Pty Ltd v Andrianakis,[24] the Court of Appeal of the Supreme Court of Victoria considered a procedural rule which provided that a statement of claim might be struck out as embarrassing or not disclosing a cause of action. After referring to the "high hurdle" which an applicant must cross and the "low bar" confronting the respondent, the Court relevantly said:

"When a defendant contends that a statement of claim should be struck out because it does not disclose a cause of action it is necessary ... to establish that it would be futile to allow the statement of claim to go forward, because it raises a claim that has no real prospect of success in the sense of being 'fanciful'. It follows that, where there is a contentious or debatable point of law which arises on a pleading, it is usually inappropriate for a trial judge or the Court of Appeal to determine the issue on a strike out application, particularly where the answer may depend upon the factual context."

The primary dispute as to whether the Reversion Trigger has occurred?

[8] To better understand the arguments on this application, it is necessary to provide an overview of the dispute encapsulated by the proceeding.[25]

[9] In the 1990's, Tri-Star appraised several coal seam gas fields in Queensland and acquired authorities to prospect and petroleum leases in relation to those fields under the Petroleum Act 1923 (Qld). Joint operating agreements were entered into by Tri- Star, or some of the plaintiffs, with other tenement holders ("the JOAs"). APLNG developed a project for the transportation for coal seam gas extracted from various tenements to Curtis Island for conversion to liquid natural gas and then export. The first defendant carried on the business of acquiring interests in gas tenements, extracting and processing coal seam gas from those tenements and transporting gas for sale.

[10] By the 2002 Deed, three of the four plaintiffs agreed to assign to the first defendant interests in the petroleum tenements and the JOAs ("the Assigned Interests") in consideration for which the first defendant agreed to pay a fixed purchase price along with vendor royalties on defined sale proceeds. The 2002 Deed provided for the retention by those plaintiffs of a 45% reversionary interest in the Assigned Interests which would automatically revert upon the occurrence of what was described as the "Reversion Trigger".

[11] The materially relevant clauses of the 2002 Deed may be set out as follows.

[12] Clause 5.4 made provision for "Retained Interests" and was in these terms:

"Notwithstanding any other provision of this Deed, the agreements to sell, transfer and assign the Assigned Interests are subject to and conditional upon the retained Royalty referred to in clause 17 and Reversionary Interest referred to in clause 16."

[13] Clause 16 made provision for what was described as the "Conditional Reversionary Interest". Clause 16.1 materially provided:

"[T]he sale of each of the Assigned Interests is subject to and conditional upon the relevant Vendor retaining a reversionary interest in its favour of an undivided 45% of all such Assigned Interests, which shall include any interest under permits or operating agreements issued in respect of the Permits or made by the parties in relation to any of the Permits after the date of Completion (the 'Retained Interest')

[T]he Purchaser shall have the full use and enjoyment of the entire interest in the Assigned Interests pending the Reversion Trigger"

[14] By clause 16.2(a), provision was made for the reversion of the Retained Interest, as follows:

"When the Reversion Trigger occurs, the interests of the Purchaser in the Assigned Interests shall automatically dilute to 55% of the total of those interests in aggregate so that the Vendors shall hold the Retained Interest in the legal and beneficial interests in the Assigned Interests. For the avoidance of doubt, the parties acknowledge and agree that the reversion of the Retained Interest to the relevant Vendors does not require any further act on the part of the Vendors or Purchaser."

[15] Clause 16.3 dealt with the meaning of the expression, "Reversion Trigger" as follows:

"The parties agree that the Reversion Trigger will be deemed to have occurred on the first day of the month following the month during which the result of the following calculation first returns a positive number (i.e., greater than zero):

Result = R - Purchase Price - COE - I - Vendor Royalty Payments - Government Royalty."

[16] The term "R" was defined in cl 16.3 to mean "...Sales Proceeds under clause 17 plus all other Revenue as defined in clause 17.2(b)(iv) derived from or in connection with the Assigned Interests."

"... (for the purposes of this clause only) the Revenue to the Purchaser or any Affiliate of the Purchaser from Petroleum from the Assigned Interests transferred by the Vendors to the Purchaser under this Deed as at the Completion Date measured at the Delivery Point, without reduction for statutory royalty or any costs and the Revenue received from Petroleum is that amount that would be determined as an arms length value by the royalty section of the Department of Natural Resources and Mines under the Petroleum Act"

"... all receipts, revenues, incomes, rights, entitlements and benefits (including future profit-sharing arrangements and recoveries under consequential loss insurance to the extent they compensate for loss of receipts, revenues, incomes, rights, entitlements or benefits that if not lost, would have constituted Revenue), without any deductions, set offs or adjustments of any kind"

[18] The formula for "R" referred to "Vendor Royalty Payments". That expression was defined to mean "all amounts payable to the Vendors as Vendor Royalty under clause 17". Clause 17.1(a) acknowledged that the Vendors had retained their interest in the Vendor Royalties and the Purchaser had agreed to pay the Vendor Royalties. Clause 17.2(a) provided that the "Vendor Royalty" was to be calculated monthly and paid monthly in arrears. Clause 17.2(b) provided that the "Vendor Royalty" was to be "3% of Sales Proceeds (plus GST)". The expression "Sales Proceeds" for the purpose of clause 17.2(b) was defined to mean "the Revenue to the Purchaser from the Assigned Interests transferred by the Vendors to the Purchaser under [the 2002 Deed] as at the Completion Date". The expression "Revenue" was defined to mean "all receipts, revenues, incomes, rights, entitlements and benefits ... without any deductions, setoffs or adjustments of any kind." The expression "Assigned Interests" included any tenement in substitution for or in replacement of a tenement forming part of the Assigned Interest.

[19] On 15 June 2004, the parties to the 2002 Deed agreed, amongst other things, that the rights and obligations of the first, second and fourth plaintiffs under that deed be assigned to, and assumed by, the third plaintiff.

[20] At the time when the 2002 Deed was executed, the majority shareholder of the first defendant was Origin Energy Ltd ("Origin"). From August 2002, APLNG or its related entities entered into agreements with related companies for the sale of gas produced from certain tenements which formed part of the Assigned Interests under the 2002 Deed ("the Reversionary Tenements"). Since 1 November 2008, APLNG has paid the expenses referable to the Reversionary Tenements in amounts relative to both interests that would have reverted had the Reversion Trigger occurred ("the Reversionary Interests") and interests that are not subject to reversion ("the Non-Reversionary Interests").

[21] Tri-Star contends that the CP payment, which as has been noted was made in late 2008, was "monetisation" of the first defendant's coal seam gas assets, and thus "Revenue". APLNG contends that reversion has not occurred and resists Tri-Star's characterisation of the CP payment. APLNG intends to submit at the trial that there are "overwhelming difficulties" with Tri-Star's suggested construction. According to APLNG's argument, Tri-Star's construction is uncommercial and would mean that the act of capitalising the first defendant in preparation for the development and exploitation of the Assigned Interests, as contemplated by the 2002 Deed, automatically deprived the first defendant of 45% of the interests which had been assigned. That primary controversy awaits resolution by trial.

APLNG's alternative pleas if the Reversion Trigger has occurred

[22] If the Reversion Trigger is found to have occurred, in the alternative to its primary defence, APLNG relies on the defences of laches, acquiescence, unclean hands, and estoppel and counterclaims for remedies including declarations in respect of estoppels, declarations in respect of, and damages for, misleading or deceptive conduct and restitution for unjust enrichment.

[23] The alternative pleas arise out of Section J of the pleading, which comprises some 120 pages. At the heart of the alternative pleas is alleged conduct by Tri-Star spanning a protracted period between 1 November 2008 and the commencement of this proceeding in October 2014. That conduct is defined by the pleading as "the Plaintiffs' Conduct". It is convenient to adopt that defined expression in these Reasons.

[24] Section J contains allegations that the Plaintiffs' Conduct occurred in a particular context in which Tri-Star and APLNG separately held various states of mind and knowledge. That is, what APLNG pleads as the facts which have occurred, the existing reality, involves not a single, discrete episode of conduct but rather conduct spanning a period of some six years comprising a series of actions and inactions by Tri-Star, which occurred when Tri-Star and APLNG held various states of mind and knowledge.

[25] The following is a high-level synopsis of the more important facts pleaded within Section J:

(a) From no later than 1 November 2008, Tri-Star knew, or held the belief, that reversion had occurred.

(b) Since November 2008, APLNG has proceeded on the basis that reversion has not occurred, including by incurring costs in developing the Assigned Interests;

(c) Tri-Star was aware that APLNG was proceeding on this basis.

(d) Until it started this proceeding in October 2014, Tri-Star did not disclose to APLNG its contention that reversion had occurred in or about or by November 2008 and that the CP payment was wholly or partly "R" within the meaning of clause 16.3 of the 2002 Deed and that Tri-Star claimed an adverse title or a right to the Reversionary Interests by way of reversion having occurred.

(e) after November 2008, Tri-Star accepted royalty payments and was aware that APLNG was making government royalty payments, and responded to cash calls and offers to enter certain gas sale agreements made by APLNG under the JOAs, all of which reflected the interests of the parties as if reversion had not occurred, without asserting that the royalty payments, cash calls and offers should reflect the post-reversion interests of the parties.

(f) in the circumstances which occurred, there was a reasonable expectation that Tri-Star would promptly inform APLNG of its belief, or intention to contend, that reversion had occurred.

(g) Tri-Star's conduct, including its silence, amounted to representations ("the Representations"), was misleading and induced APLNG to make assumptions ("the APLNG Assumptions") including that reversion had not occurred and that Tri-Star would not contend that reversion had occurred because of the CP payment.

(h) on 28 July 2011, the APLNG Board approved a final investment decision on the first phase of a two train coal seam gas ("CSG") to liquefied natural gas ("LNG") project, with each LNG train to have a nameplate capacity of 4.5 million tonnes per annum, which decision is referred to as "FID 1".

(i) on or about 9 August 2011, pursuant to a written agreement dated 21 April 2011 ("the First Sinopec Subscription Agreement") between APLNG, Origin, ConocoPhillips Australia Pacific LNG Pty Ltd ("ConocoPhillips Australia"), ConocoPhillips, Sinopec Australia Pacific LNG Pty Ltd ("Sinopec") and China Petrochemical Corporation, APLNG issued to Sinopec, 35, 313,954 ordinary shares in APLNG representing 15 per cent of the number of shares on issue by APLNG and Sinopec paid an amount of US$1,764,705,882.35 to APLNG in respect of those shares ("the First Sinopec Payment").

[26] That synopsis reveals these contentions made by APLNG:

(a) Since 2008, Tri-Star knew of the facts now relied on as giving rise to reversion,[26] knew of its contentions or held the belief that reversion had occurred[27] and knew that APLNG was expending large amounts in developing the tenements in connection with an export project.[28]

(b) Despite this knowledge, Tri-Star, by its conduct[29] and silence[30] represented that reversion had not occurred in 2008 and promised that it would not contend otherwise.[31]

(c) APLNG relied on the Representations and made the APLNG Assumptions.[32]

(d) APLNG will suffer detriment,[33] if Tri-Star is not estopped from resiling from the Representations;

(e) APLNG has suffered loss and damage by reason of Tri-Star's misleading or deceptive conduct;[34]

(f) APLNG is entitled to restitution for Tri-Star's unjust enrichment as a result of the large amounts of money APLNG has spent since 2008 on the Reversionary Interests.[35]

The framework of Tri-Star's strike out complaints

[27] It is convenient, at this point, to note what is not in issue on this application.

[28] The facts alleged by section J of the pleading, including the Plaintiffs' Conduct, span a period between November 2008 and October 2014. The Representations are alleged to have been made by the Plaintiffs' Conduct,[36] which is alleged to have occurred since 1 November 2008, the date defined by the pleading as "the First Alleged Reversion Date."[37] The pleading also alleges that since 1 November 2008, Tri-Star knew that APLNG was relying upon the Representations[38] and, again that since 1 November 2008, APLNG has suffered detriment.[39] These pleas apparently contemplate that the Representations were made as of 1 November 2008 and thereafter continued. The facts which gave rise to the Representations as of 1 November 2008 and to reliance and detriment as and from that date were not the focus of Tri-Star's attack on the pleading. Tri-Star raised no issue or complaint about these matters. Further, the pleading seeks to differentiate between "the extent the Representations were made" at different points in time.[40] That the pleading seeks to differentiate between the extent of the Representations at any given time, might conceivably raise issues as to the facts which constitute the Representations and the acts of reliance by APLNG, including by whom, at the different times. Again, Tri- Star raised no issue or complaint about these matters.

[29] As to what is in issue on this application, Tri-Star made complaints about the pleading of the Representations in the context of the estoppel and misleading and deceptive conduct pleas. Tri-Star contends that the Representations and the APLNG Assumptions ought to be struck out under r 171(1)(a) because they are "untenable and cannot possibly succeed". [41] In relation to the estoppel pleas, there were two aspects to Tri-Star's complaints about the Representations. First, Tri-Star contends that the facts pleaded cannot have given rise to a duty on its part to disclose that reversion occurred in late 2008 with the making of the CP payment. Tri-Star submits that unless there was a duty to disclose or a duty to speak, no representations can have arisen from the pleaded facts, which are said to involve either silence or conduct that is not inconsistent with reversion having occurred. Second, Tri-Star submits that even if there were a duty to speak, the pleaded facts, at their highest, amount to a representation of Tri-Star's opinion, such a representation being incapable of establishing an estoppel.

[30] As to the misleading and deceptive conduct claims, there are two aspects to Tri-Star's complaints. First, it is said that the pleading does not support an allegation that Tri-Star represented by its silence that it would not contend that reversion had occurred. For that reason, the pleaded allegations concerning the absence of reasonable grounds are submitted to be irrelevant. Second, to the extent that the pleading incorporates an allegation of a "reasonable expectation" that Tri-Star would disclose matters about which it remained silent, there is said to be an absence of any foundation in the pleading for an expectation that Tri-Star would inform APLNG not of an existing fact, but of Tri-Star's opinion as to the effect of the CP payment.

[31] The pleading of a proprietary estoppel by standing was said to be untenable because Tri-Star "could not have had the knowledge required to give rise to a proprietary estoppel by standing by".[42] There is said to be a further fundamental problem with the claim because any "standing by" must have ceased upon APLNG's lawyers having received a letter from Tri-Star's lawyers dated 28 May 2012 ("the 28 May 2012 Letter") by which Tri-Star is said to have notified APLNG of its contention that the CP payment should be included in the reversion calculations under the 2002 Deed.

[32] As to causation, Tri-Star variously submitted that there are defects in the allegations of detrimental reliance including the pleas of loss and damage and that, in any case, the causation case "is hopeless". Relying upon that last characterisation, the estoppel and misleading or deceptive conduct claims are described as "an invention that defies reality".[43] Tri-Star asserts numerous pleading defects in the allegations of detrimental reliance. First, Tri-Star contends that there is a requirement to plead "but for reliance" with respect to allegations of detrimental reliance for both the estoppel and misleading or deceptive conduct cases. Beyond that complaint, Tri-Star contends that the pleading otherwise inadequately pleads detrimental reliance. In relation to the submission that the causation case is "hopeless", Tri-Star, invoked the language of summary judgment jurisprudence, submitting that APLNG has "no reasonable prospect of establishing that it in any way relied upon [the Representations] or that, had Tri-Star revealed earlier its contention that the [CP payment] caused reversion under the 2002 Deed ...., APLNG would have acted differently and in the manner now alleged".[44]

[33] Finally, Tri-Star contends that the unjust enrichment and the estoppel by convention claims ought to be struck out for reasons, some of which relate to its complaints about the estoppel and misleading or deceptive conduct claims. Tri-Star also seeks to strike out several miscellaneous paragraphs which are variously said to suffer from specific pleading deficiencies.

[34] On the basis that it "cannot have made the alleged representations", Tri-Star seeks to strike out paragraphs 214, 215, 225, 226 (the words "by the Plaintiffs' Conduct the plaintiffs induced"), 227(b), 228, 229, 231 (b)-(c), 236 to 239, 242 and 245 (in so far as those paragraphs rely on paragraphs 236 to 239 and 246 to 265A)

[35] The Representations are alleged to have arisen "by the Plaintiff's Conduct". The Plaintiff's Conduct includes various allegations about Tri-Star's action and inaction and Tri-Star's and APLNG's knowledge and states of mind.

[36] As to Tri-Star's knowledge and states of mind, the pleading alleges that from no later than October to December 2008 or alternatively before 28 July 2011 (the date the APLNG Board approved FID 1) or alternatively before 4 July 2012 (the date the APLNG Board approved FID 2), Tri-Star knew of "matters and contentions" being that:

(a) the CP payment was "Revenue" within the meaning of clause 17.2(b)(v) of the 2002 Deed;

(b) the CP payment was to be included in "R" without deduction, adjustment or set off of any kind;

(c) by 29 October 2008, the result of the calculation in clause 16.3 of the 2002 Deed returned a positive number;

(d) by no later than 1 November 2008, the Reversion Trigger had occurred;

(e) the CP payment was referrable to an opportunity to participate in an integrated CSG to LNG project via a shareholding in APLNG;

(f) the proposed CSG to LNG project involved the use of reversionary CSG produced from the Reversionary Tenements.

(a) since in or about April 2011, or alternately before 28 July 2011 or alternatively before 21 July 2012, Tri-Star knew of the First Sinopec Subscription Agreement and the First Sinopec Payment;

(b) since in or about January 2012 or 4 July 2012, Tri-Star knew of the Second Sinopec Subscription Agreement and the Second Sinopec Payment.

[38] It is then alleged that if reversion occurred by 1 November 2008, Tri-Star:

(a) "knew that reversion had in fact occurred at around [that time]";

(b) alternatively "ought to have reasonably known on the basis of [its] interpretation of the 2002 Deed and [its] contentions in this proceeding that reversion had occurred at around [that time]";

(c) further and alternatively "knew of [its] contentions or held the belief that reversion had occurred at around [that time] ... alternatively before 28 July 2011 ... and in the further alternative before 4 July 2012".

[39] Against the background of those allegations, the pleading alleges that Tri-Star did not disclose the following matters ("the Undisclosed Matters") to APLNG prior to the commencement of this proceeding on 24 October 2014 namely:

(a) Tri-Star's contention that reversion had occurred by 1 November 2008;

(b) any claim of an adverse title or right to the Reversionary Interests by way of the occurrence of reversion;

(c) the contention that the CP payment was wholly or partly "R" within the meaning of clause 16.3 of the 2002 Deed such as to cause the occurrence of reversion.

[40] In terms of APLNG's relevant state of mind, the pleading alleges that at all material times APLNG believed that the CP payment was not wholly or partly characterised properly as an amount which constituted part of "R" for the purpose of the calculation required by clause 16.3 of the 2002 Deed, the Reversion Trigger had not occurred, Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment and there was no contention made by Tri-Star in the nature of the Undisclosed Matters. The pleading notably alleges that the Plaintiff's Conduct induced APLNG to have or continue to hold those beliefs.

[41] Broadly summarised, the Plaintiff's Conduct comprises:

(a) Tri-Star's failure to pay or reimburse APLNG for expenses paid by APLNG which related to the Reversionary Interests (paragraphs 198 to 199);

(b) Tri-Star making elections and payments in respect of its working interests under the JOAs but not in respect of the Reversionary Interests (paragraphs 200 to 2003);

(c) Tri-Star making elections to not participate in agreements for the sale of gas in respect of its working interests under the JOAs and not objecting to APLNG participating in those agreements in proportions relative to both the Reversionary Interests and Non-Reversionary Interests (paragraphs 204 and 205);

(d) Tri-Star's acceptance of Overpaid Vendor Royalty on the basis that reversion had not occurred and in circumstances where Tri-Star had no entitlement to the Vendor Royalty if reversion had occurred (paragraphs 220 and 221);

(e) Tri-Star permitting APLNG to pay government royalties on the basis that reversion had not occurred and failing to pay or contribute to government royalties attributable to the Reversionary Interests (paragraphs 222 and 223); and

(f) Tri-Star's failure to take steps to seek an assignment or retransfer from APLNG of the Reversionary Interests or to seek to have APLNG recognise the occurrence of reversion (paragraph 224);

(g) Tri-Star's failure, despite its knowledge, to disclose the Undisclosed Matters (paragraph 214).

(a) the CP payment was not wholly or partly characterised properly as an amount which constituted part of "R" for the purpose of the calculation required by clause 16.3 of the 2002 Deed;

(b) the Reversion Trigger had not occurred by reason of the CP payment;

(c) Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment;

(d) impliedly, Tri-Star had reasonable grounds for making the representation that it would not contend that the Reversion Trigger had occurred;

(e) the Undisclosed Matters did not exist and Tri-Star did not contend and would not contend to the effect of any of the Undisclosed Matters.

[43] It may be observed that some of the Representations involve an existing state of affairs and others, namely those concerned with what Tri-Star would not contend, concern future matters. That distinction is significant to the characterisation of any estoppel. A common law estoppel by representation requires a representation of an existing state of affairs.[45] An equitable estoppel might encompass encouragement by the making of a promise concerning some representation about future conduct.[46]

[44] The APLNG Assumptions are pleaded in terms that the Plaintiff's Conduct induced APLNG to assume and continue to assume that:

(a) the CP payment was not wholly, or partly characterised properly as an amount which constituted part of "R" for the purpose of the calculation required by clause 16.3 of the 2002 Deed;

(b) the Reversion Trigger had not occurred by reason of the CP payment;

(c) Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment;

(d) the Undisclosed Matters did not exist and there was no contention of Tri-Star's in the nature of the Undisclosed Matters.

[45] It is alleged that there was a reasonable expectation that Tri-Star would, or further or alternatively had a duty in equity to, "promptly disclose and assert [the Undisclosed Matters] to APLNG if they existed or alternatively were or would be contended to exist". That expectation or duty is alleged to have arisen in circumstances where:

(a) the Undisclosed Matters were important matters relevant to the parties' respective rights and obligations as to the timing and circumstances of reversion, ownership of and ongoing rights of access to and use of the CSG produced from the Reversionary Tenements, expenditure on the Reversionary Tenements and development exploitation and improvement of the Reversionary Tenements;

(b) the Undisclosed Matters were important matters relevant to APLNG's consideration in deciding whether to approve FID 1 on 28 July 2011, or alternatively FID2 on 4 July 2012 and steps taken thereafter in pursuit of the CSG to LNG project because that project involved the use of CSG produced from the Reversionary Tenements, expenditure of substantial amounts to develop, exploit and improve the Reversionary Tenements, committing APLNG and the APLNG parties to the supply of LNG pursuant to long term off take contracts based on reversion having not occurred and committing APLNG to two LNG trains each with a capacity of 4.5 mtpa based on reversion having not occurred with reliance upon access to the CSG from the Reversionary Tenements;

(c) Tri-Star knew, or alternatively, ought reasonably to have known of the matters referred to in (a) and (b);

(d) Tri-Star knew, and further or alternatively believed, or alternatively ought to have reasonably known, as was the fact, that APLNG:

(a) was not aware of the Undisclosed Matters;

(b) was proceeding on the belief and assumption that reversion had not occurred and there was no contention that reversion had occurred;

(c) was proceeding on the belief and assumption that the CP payment was not characterised as "R", and that there was no subsisting or ongoing contention of Tri-Star that the CP payment was characterised as "R" for the Reversion Trigger.

[46] The allegation that Tri-Star knew, as was the fact, that APLNG was proceeding in the belief and assumption that the CP payment was not characterised as "R" and that there was no subsisting or ongoing contention of Tri-Star that the CP payment was characterised as "R" for the Reversion Trigger references circumstances including an exchange of correspondence the 28 May 2012 letter.

[47] On 28 May 2012, Corrs Chambers Westgarth Lawyers, acting for Tri-Star, sent the 28 May 2012 letter to APLNG. By a letter dated 6 June 2012 ("the 6 June 2012 Letter"), Clayton Utz, acting for APLNG, replied to the 28 May 2012 Letter.

[48] The 28 May 2012 Letter contained an introductory heading "Provision of Information". The letter asserted that Tri-Star had advised APLNG that it had not provided and was not providing access to information and documentation that APLNG was contractually obliged to provide to Tri-Star. The letter then stated "... the purpose of this letter is to address in a more comprehensive manner Tri-Star's concerns relating to the lack of provision of access to information and those records and to make demand for the immediate provision of this information and access to the necessary records".

[49] The 28 May 2012 Letter referred to the 2002 Deed and relevantly stated:

"The Deed provided that the transfers to APLNG were subject to Tri-Star retaining a reversionary interest in its favour with respect to an undivided 45% interest of all of the Assigned Interests which will revert to Tri-Star on the occurrence of the Reversion Trigger. The occurrence of the Reversion Trigger is determined pursuant to formula contained in the Deed which takes account of revenues, the purchase price paid by APLNG under the Deed, vendor and government royalty payments, interest and expenditure, all of which are defined in the Deed.

On 15 June 2004 Tri-Star Petroleum Company, Tri-Star America Trading Company and West Texas Oil and Gas Corporation assigned their interests in the Deed to Tri-Star Australia Holding Company pursuant to a Deed of Assignment and Assumption. APLNG consented to the assignment.

The description of the relevant landholdings and tenures which existed at the time that the Deed was signed has varied over time as a result of relinquishments that have occurred. Also, the nature of the tenures has changed as a result of new interests being granted etc.

Our clients have also acquired further working interests in the relevant tenements in the intervening period.

Annexure A to this letter is a schedule which sets out the relevant tenures, Tri-Star's current working interests in those tenures and the working interests that Tri-Star will hold in the tenures once reversion under the Deed and Project Payout under the Joint Operating Agreements occurs."

[50] The 28 May 2012 Letter went on to discuss in detail APLNG's obligations to provide information and why Tri-Star required that information. Relevantly, one of the reasons why Tri-Star required access to information was expressed to be "to establish accurately and reliably the status of the Reversion Trigger under the Deed".

"Sell Down of Interests in APLNG to ConocoPhillips and Sinopec

From publicly available information Tri-Star is aware of the following:

* on 29 October 2008 APLNG issued 100 million new shares

and ConocoPhillips paid $75.626683491 for each share or a total payment of $7,562,688,343.91;

* at that date, the amount that remained unpaid on each

share was S52.0113857121, meaning that there was a total of $5,201,138,571.21 in unpaid share capital;

* the result of the share issue on 29 October 2008 was that 50% of the shares in APLNG were held by ConocoPhillips;

* in August 2011 Sinopec and APLNG completed a subscription agreement pursuant to which Sinopec acquired a 15% interest in APLNG and paid to it US$1,765,000,000.

* in January 2012 Sinopec and APLNG completed a further subscription agreement pursuant to which Sinopec acquired a further interest in APLNG which lifted its shareholding to 25%, Sinopec paid To APLNG US$1,100,000,000;

* currently APLNG is owned 37.5% by Origin Energy Limited, 37.5% by ConocoPhillips and 25% by Sinopec.

On their face, the ConocoPhillips and Sinopec payments to APLNG for shares may be caught by the definition of Revenue as that term is defined in clause 17.2 of the Deed.

Further, any other transactions by which APLNG has sought to commercialise or monetise the CSG assets which are the subject of the Deed would also seem to come within the definition of Revenue. As such, it would seem that these amounts should be included in the Reversion Trigger calculations.

If APLNG disagrees that these payments should form part of the Reversion Trigger calculation it should provide an explanation for its view. However, in the present circumstances Tri-Star requires that APLNG:

(a) provides to it copies of all documents which relate to the sell downs to ConocoPhillips and to Sinopec as well as any other transactions by which APLNG has sought to commercialise or monetise the CSG assets; and

(b) include these proceeds as part of Revenue in the Reversion Trigger calculations required above."

[52] The 28 May 2012 Letter concluded by noting that Tri-Star required APLNG to confirm by 4pm on Wednesday 6 June 2012 that all the requested information and access to documents would be provided and that failing the receipt of such unconditional confirmation Tri-Star would take the steps necessary to enforce its rights.

[53] The 6 June 2012 Letter was apparently an attempt to address in a comprehensive manner Tri-Star's concerns relating to the lack of provision of, and access to, information and records. The 6 June 2012 Letter noted that the determination of the Reversion Trigger had been a disputed matter under a mutual confidentiality Deed and been the subject of a without prejudice meetings. The letter then stated:

"However, Tri-Star has no contractual entitlement under the Deed to a statement setting out APLNG's calculation in relation to the 'Reversion Trigger'. The 'Reversion Trigger' is an event that has deemed to have occur if specified conditions are satisfied. This event will (or will not) occur as a matter of fact. ... notwithstanding Tri-Star has no contractual entitlement to information beyond that is noted above, APLNG does understand Tri-Star's interest in the 'Reversion Trigger' calculation. We are instructed that APLNG is prepared to continue working with Tri-Star in the without prejudice process to agree information that will be provided to Tri-Star to facilitate the calculated of the 'Reversion Trigger'".

[54] In relation to the sell down of interests in APLNG, the 6 June 2012 Letter simply stated as follows:

"APLNG disagrees that any payments connected with APLNG's dealings with ConocoPhillips and Sinopec come within the definition of Sales Proceeds or Revenue in clause 17.2 of the Deed."

[55] The 6 June 2012 Letter ended with the following paragraphs:

APLNG has advised that it will provide Tri-Star with a range of material by Friday, 29 June 2012. As you have acknowledged, the requested documents will take some time for APLNG to compile, but where the documents can be produced earlier than 29 June 2012 they will be.

As to a number of the requests, APLNG has sought clarification or further information and we look forward to hearing from you as to those matters.

Where there is disagreement as to Tri-Star's entitlement to the requested information or documents it is APLNG's intention to work through that disagreement in a constructive manner, both within the without prejudice discussions, and if Tri-Star requires, outside them."

[56] The pleading alleges facts which occurred after the exchange of the 28 May 2012 and 6 June 2012 Letters which are relevant to any consideration of the meaning and significance of this correspondence. Relevantly, the pleading alleges that Tri-Star did not respond to the 6 June 2012 Letter and, until commencing this proceeding, never suggested that Tri-Star did not accept the position of APLNG as stated in the 6 June 2012 Letter.

[57] Tri-Star's submissions did not, save for in one respect, and then only in a limited way which I have addressed later, attack the adequacy or sufficiency of the various allegations made about its relevant knowledge.

[58] Notably, for the purpose of this application and the paragraphs of the pleading sought to be struck out by the application, Tri-Star makes no complaint whatsoever about the allegations that it:

(a) knew that reversion had in fact occurred at around the time of the First Alleged Reversion Date;[47]

(b) alternatively, ought to have reasonably known on the basis of its interpretation of the 2002 Deed and its contentions in this proceeding that reversion had occurred at around the time of the First Alleged Reversion Date;[48]

(c) further or alternatively knew of its contentions of held the belief that reversion had occurred at around the time of the First Alleged Reversion Date, alternatively before 28 July 2011 or in the further alternative before 4 July 2012;[49]

(d) knew of matters alleged in paragraphs 165 to 206 of the pleading since on or about when those matters occurred, those paragraphs including, by way of example only, facts or matters such as APLNG entering into agreements for the sale of CSG from the reversionary tenements (para 192) and paying government royalties on the basis that reversion had not occurred (para 196).[50]

[59] Tri-Star sought to strike out paragraph 215 of the pleading in the context of its complaints about the pleading of the Representations but it made no complaint, as a matter of pleading, about the allegations of its knowledge as contained in paragraphs 215(c) and (d) of the pleading. Notably, those paragraphs alleged that Tri-Star:

(a) knew that the Undisclosed Matters were important matters relevant to the timing and circumstances of reversion, ownership and rights of access to CSG produced from the Reversionary Tenements, expenditure on the Reversionary Tenements and development, exploitation and improvement of the Reversionary Tenements;[51]

(b) knew that the Undisclosed Matters were important matters relevant to APLNG's consideration in deciding whether to approve FID 1 on 28 July 2011 or alternatively to approve FID 2 on 4 July 2012 and steps taken thereafter in pursuit of the project because the project involved, inter alia, committing APLNG to the development of the project and the supply of LNG pursuant to long term off take contracts based on reversion having not occurred and committing APLNG to a project based on reversion having not occurred with reliance upon access to the CSG from the Reversionary Tenements;[52]

(c) knew that APLNG was unaware of the Undisclosed Matters;[53]

(d) knew that APLNG, in taking FID 1 and FID 2, and in expending money, skill, time and effort on the Reversionary Interests in the progressing the project the subject of FID 1 and FID 2, was proceeding on the belief and assumption that reversion had not occurred and there was no contention of Tri-Star that reversion had occurred or any claim of an adverse title to the Reversionary Interests;[54]

(e) knew that APLNG was proceeding on the belief and assumption that the CP payment was not characterised as "R" and there was no subsisting or ongoing contention by Tri-Star that the CP payment was characterised as "R".[55]

[60] Tri-Star relied upon two fundamental points in seeking to strike out the Representations and the Assumptions in the context of the estoppel plea which were to the effect that the pleaded facts did not give rise to a "duty on the part of Tri-Star to disclose its contention that reversion had occurred in around November 2008" and that, even assuming that a duty arose, the pleaded facts at most gave rise to representations of Tri-Star's opinion as to the relevance of the CP payment to reversion and whether reversion had occurred. These fundamental points were apparently advanced on the premise that, for the purpose of this aspect of the application, the only relevant estoppel in contemplation was an estoppel by representation.[56] That premise was controversial. APLNG submitted that the pleading also satisfied the requirements for an equitable estoppel arising by encouragement by the making of a promise. APLNG emphasised the content of paragraphs 225(c) and (e) of the pleading which involved representations to the effect that Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment by no later than the First Alleged Reversion Date and would not contend to the effect of any of the Undisclosed Matters.[57] I accept APLNG's submission that the Representations, properly characterised for the purposes of this application, include representations of fact and promissory statements.[58] In my consideration, it would be an error to approach this strike out application on the basis that the only form of estoppel contemplated by the pleading of the Representations is an estoppel by representation or common law estoppel. An equitable estoppel arising by encouragement by the making of a promise is plainly contemplated by the pleading of the Representations.

[61] In Thompson v Palmer,[59] Dixon J made the following statement about common law estoppel:

"The object of estoppel in pais is to prevent an unjust departure by one person from an assumption adopted by another as the basis of some act or omission which, unless the assumption be adhered to, would operate to that other's detriment. Whether a departure by a party from the assumption should be considered unjust and inadmissible depends on the part taken by him in occasioning its adoption by the other party. He may be required to abide by the assumption because it formed the conventional basis upon which the parties entered into contractual or other mutual relations, such as bailments; or because he has exercised against the other party rights which would exist only if the assumption were correct ... or because knowing the mistake the other laboured under, he refrained from correcting him when it was his duty to do so; or because his imprudence, where care was required of him, was the proximate cause of the other party's adopting and acting upon the faith of the assumption; or because he directly made representations upon which the other party founded the assumption."

[62] This statement of principle makes plain that whether a departure by a person from an assumption should be considered unjust depends on the part taken by that person in occasioning its adoption by the other person.[60] Shortly after Thompson, in Grundt v Great Boulder Pty Gold Mines Ltd,[61] Dixon J provided the following further explanation of the underlying principle of common law estoppel:

"The principle upon which estoppel in pais is founded is that the law should not permit an unjust departure by a party from an assumption of fact which he has caused another party to adopt or accept for the purpose of their legal relation. This is, of course, a very general statement. But it is the basis of the rules governing estoppel. Those rules work out the more precise grounds upon which the law holds a party disentitled to depart from an assumption in the assertion of rights against another. One condition appears always to be indispensable. That other must have so acted or abstained from acting upon the footing of the state of affairs assumed that he would suffer a detriment if the opposite party were afterwards allowed to set up rights against him inconsistent with the assumption. In stating this essential condition, particularly where the estoppel flows from representation, it is often said simply that the party asserting the estoppel must have been induced to act to his detriment. Although substantially such a statement is correct and leads to no misunderstanding it does not bring out clearly the basal purpose of the doctrine. That purpose is to avoid or prevent a detriment to the party asserting the estoppel by compelling the opposite party to adhere to the assumption upon which the former acted or abstained from acting. This means that the real detriment or harm from which the law seeks to give protection is that which would flow from the change of position if the assumption were deserted that led to it."

[63] Later in his Honour's reasons in Grundt,[62] Dixon J observed that before a person can be estopped the person "must have played such a part in the adoption of the assumption that it would be unfair or unjust if he were left free to ignore it". His Honour said that the law had defined "with more or less completeness the kinds of participation in the making or acceptance of the assumption that will suffice to preclude the party if the other requirements for an estoppel are satisfied."[63] His Honour noted that a "brief statement of the recognised grounds of preclusion" was contained in the passage of his Honour's earlier reasons in Thompson, being the passage set out above.[64] When regard is had to that "brief statement", APLNG's pleaded common law estoppel case is more aligned with or directed to the last recognised ground of preclusion, namely where a person has "made representations upon which the other party founded the assumption".[65]

[64] In Combe v Combe[66] Lord Denning described promissory estoppel as founded on "a promise or assurance which was intended to affect the legal relations between them". In Waltons Stores (Interstate) Ltd v Maher,[67] Brennan J said:

"In all cases where an equity created by estoppel is raised, the party raising the equity has acted or abstained from acting on an assumption or expectation as to the legal relationship between himself and the party who induced him to adopt the assumption or expectation. The assumption or expectation does not relate to mere facts, whether existing or future ... though the party raising the estoppel may be under no mistake as to the facts, he assumes that a particular legal relationship exists or expects that a particular legal relationship will exist between himself and the party who induced the assumption or expectation ... but, if the party raising the estoppel is induced by the other party's promise to adopt an assumption or expectation, the promise must be intended by the promisor and understood by the promisee to affect their legal relations."

[65] In Kramer v Stone,[68] the plurality[69] identified four elements for an equitable estoppel arising by reason of encouragement from a promise. The first element involves a "clear and unequivocal promise" which will generally concern some representation about future conduct.[70] The second element is that "a reasonable person in the promisor's position must have expected or intended (or the promisor did actually expect or intend) that the promisee would rely upon the promise by some action, omission or course of conduct."[71] In that sense the promise has to have been an "encouragement" for the promisee to act.[72]

[66] Tri-Star's submissions at various times invoked the language, or label, of a "duty to speak" as somehow determinative of whether "mere silence" might found an estoppel. I did not find those submissions to be particularly helpful in the determination of the real issues raised by this aspect of the strike out application. In 183 Eastwood Pty Ltd v Dragon Property Development & Investment Pty Ltd, [73] Ward P[74] observed that there was some force in a submission made in that case to the effect that describing the test in terms of a duty "tends to distract from the critical question of whether it is unjust for there to be a departure from the assumption adopted". In Moorgate Mercantile Credit Co Ltd v Twitchings[75], Lord Wilberforce, in the context of a case involving estoppel by silence and inaction relevantly said:

"I think that the test of duty is one which can safely be applied so long as it is understood what we mean.... but I think that there is a danger in some contexts ... of bringing in with it some of the accretions which it has gained - proximity, propinquity, foreseeability - which may be useful or at least unavoidable in other contexts. What I think we are looking for here is an answer to the question whether, having regard to the situation in which the relevant transaction occurred, as known to both parties, a reasonable man in the position of the 'acquirer' of the property, would expect the 'owner' acting honestly and responsibly, if he claimed any title in the property, to take steps to make that claim known to, and discoverable by the 'acquirer' and whether, in the face of an omission to do so, the 'acquirer' could reasonably assume that no such title was claimed."

[67] Lord Bingham has said that a duty to speak may arise "where a reasonable man would expect the person against whom the estoppel is raised, acting honestly and responsibly to bring the true facts to the attention of the other party known by him to be under a mistake as to their respective rights and obligations."[76] In Barport Pty Ltd v Baum,[77] the Victorian Court of Appeal, after having observed that "silence may give rise to an estoppel if having regard to the nature of the relationship, the nature of the assumption or the circumstances as a whole there is a duty to speak", went on to state that "... the import of the silence must be clear and unequivocal and must be assessed in light of the broader context". One thing which is sufficiently clear is that the meaning of silence is not to be assessed in a vacuum without regard to the surrounding circumstances. It would be hazardous to attempt to ascertain the true meaning of silence, particularly in a broader factual context, on the face of a pleading alone without the benefit of facts found at trial. In Orion Finance Ltd v J D Williams & Company Ltd[78], Evans LJ relevantly said:

"Silence never stands alone, or in a vacuum. There must always be surrounding circumstances ... which give the silence its meaning ...[T]he inquiry whether there was a duty to speak merely restates the problem: were the circumstances such that silence had a legal effect?"

[68] I have concluded that it would be inappropriate to strike out the Representations and APLNG's Assumptions in the context of the estoppel and misleading or deceptive conduct claims on the asserted basis that they are "untenable and cannot possibly succeed". My reasoning for that conclusion is as follows.

(a) This is not a simplistic situation where Tri-Star is alleged to have said and done nothing. The pleaded case expressly relies on conduct. The conduct involves making payments and elections, and failing to make payments or reimbursements, all of which is said to be inconsistent with reversion having occurred. The pleading, properly construed, relies upon a mixture of conduct and silence in circumstances of alleged relevant knowledge. Whether the Representations were made will depend upon a close examination of all of the surrounding circumstances or the situation in which the relevant conduct and silence occurred. The evidence at trial may well colour the proper characterisation of Tri-Star's conduct and silence.

(b) Tri-Star's written submissions acknowledged that the pleading relied on conduct but, for the purposes of the strike out application, sought to characterise "much of" the alleged conduct as conduct that was "not inconsistent with reversion having occurred". That language implicitly accepted that at least part of the conduct was inconsistent with reversion having occurred. But, in any case, the proper characterisation of the conduct will depend upon findings of fact made at trial with the benefit of evidence which enables the required close examination of the surrounding circumstances in which the conduct occurred;

(c) Tri-Star characterised the Representations as "at most" representations of Tri-Star's opinion as to the relevance of the CP payment and whether reversion had occurred. That characterisation did not fairly reflect the true nature and extent of the Representations. The Representations include representations to the effect that Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment and did not and would not contend to the effect of any of the Undisclosed Matters;

(d) In any event, the suggested characterisation of parts of the Representations as matters of opinion, is in my consideration, an unsatisfactory basis for the determination of a strike out application in the particular circumstances of this case. Whether or not a statement is properly to be regarded as one of fact or opinion, depends upon all the relevant circumstances known to the representee, including the form and subject matter of the statement, and the actual and likely personal knowledge of the representor. To the extent that the Representations were sought to be characterised as "opinions' they arguably are properly characterised as involving representations of fact to the extent that they involve statements about private legal rights or the effect of documents. It is well arguable by reference to authority that the latter characterisation is available in cases of estoppel by representation or promissory estoppel, and is not confined to cases involving estoppel by convention;

[69] There are two further submissions which fall to be considered at this point.

[70] Tri-Star made a submission addressing the adequacy of the pleading in paragraphs 229 and 231 which alleges that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the Representations or that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the APLNG Assumptions. These paragraphs allege an inference of knowledge or intention from "the matters pleaded in paragraphs 198 to 219(e)". It was submitted that because those matters did not support the proposition that APLNG took steps in reliance on the Representations, "it follow[ed]" that those matters could not support an inference of knowledge or intention by Tr-Star in relation to reliance upon the Representations or APLNG Assumptions. I reject that submission.

[71] Paragraphs 198 to 219(e) include allegations about Tri-Star's actions and inaction and knowledge including Tri-Star's knowledge that APLNG was unaware of the Undisclosed Matters, the Undisclosed Matters were important matters and APLNG was proceeding in the belief and on the assumption that reversion had not occurred, there was no contention that reversion had occurred, the CP payment was not characterised as "R" and there was no subsisting or ongoing contention by Tri-Star that the CP payment was characterised as "R". The allegation that Tri-Star knew that the Undisclosed Matters were important matters is particularly significant. The terms of that allegation are that Tri-Star knew that the Undisclosed Matters were important matters relevant to APLNG's consideration in deciding whether to approve FID 1 or alternatively FID 2 and steps taken thereafter in pursuit of the project because the project involved the use of CSG produced from the Reversionary Tenements, committing APLNG to the development of the project and the supply of LNG pursuant to long term off take contracts based on reversion having not occurred with reliance upon access to the CSG from the Reversionary Tenements.[87] It may also be observed that paragraphs 200 to 205 of the pleading allege conduct by Tri-Star which is effectively predicated on reversion having not occurred. Paragraphs 198 to 219(e) when considered in their entirety, and having particular regard to the allegations of Tri-Star's knowledge which are not sought to be struck out, provide a sufficiently clear basis for a pleading by way of inference to the effect that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the Representations or that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the APLNG Assumptions.

[72] Tri-Star's submissions about paragraphs 229 and 231, to some extent misconstrued the pleading. By the initial part of the pleading, APLNG alleges a series of acts and conduct which occurred in a context of alleged knowledge which gave rise to the Representations and the APLNG Assumptions. By paragraph 228 of the pleading, APLNG alleges that it relied upon the Representations by acting in an identified way. Tri-Star's complaint that the matters in paragraphs 198 to 219(e) do not support the allegation that APLNG in fact relied upon the Representations introduces something of a false issue. APLNG does not rely upon paragraphs 198 to 219(e) to allege reliance as a matter of fact. Rather, those paragraphs are legitimately relied upon as a basis from which an inference can be drawn to the effect that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the Representations or that Tri-Star knew that APLNG was relying, or intended APLNG to rely, upon the APLNG Assumptions.

[73] Tri-Star submitted that it was necessary for APLNG to plead that it needed to have ownership of gas reserves which included all of the Retained Interests in order to make the investment decisions and agreements that it ultimately made. The submission contended that there was an assumption in APLNG's case that if APLNG did not own the gas the subject of the Retained Interests it would not have proceeded. That was explained in Tri-Star's oral submissions in terms that "...one asks the question, in our submission, how can it properly be said that Tri-Star knew, as it's alleged, that FID 1 and FID 2 were made in reliance upon a supposed representation that Tri-Star's position was that reversion had not occurred when there's nothing said to be disclosed to Tri-Star which says 'we need your gas otherwise these things can't go ahead'".[88] On my reading of the pleading, it is not a necessary part of APLNG's case to allege that it required ownership of gas reserves which included all of the Retained Interests in order to make the investment decisions and agreements that it made. I reject Tri-Star's submission to the effect that the pleading is deficient because there "is no suggestion ... that the decisions were made only because APLNG regarded itself as having access to the reversionary interest gas". I accept APLNG's submission that it does not allege or need to allege that it required all the gas the subject of the Retained Interests or else it would not have proceeded with any part of the project.

[74] The misleading or deceptive conduct case relies upon Tri-Star's conduct which gave rise to the Representations. This alternative case is premised on the CP payment constituting "R" for the purpose of the calculation required by clause 16.3 of the 2002 Deed, the Reversion Trigger having occurred by 1 November 2008 and the Undisclosed Matters having existed. In that alternative scenario, APLNG pleads that Tri-Star's conduct was misleading and deceptive in circumstances where:

(a) Tri-Star had no reasonable grounds for representing that reversion had not occurred by reason of the CP payment;

(b) Tri-Star had no reasonable grounds for representing that it would not contend that reversion had occurred by reason of the CP payment;

(c) Tri-Star failed to disclose the Undisclosed Matters in circumstances where it knew or held the belief that reversion had occurred, there was a reasonable expectation that the Undisclosed Matters would have been promptly disclosed to APLNG and where a failure to disclose or assert the Undisclosed Matters was likely to lead APLNG into believing or assuming that there was no contention, and there would be no contention, that reversion had occurred by reason of the CP payment or that reversion had occurred.

[75] Whether conduct, in circumstances of knowledge and silence, is misleading or deceptive requires a close analysis of all the circumstances of the transaction[89]. In Pegella Pty Ltd v National Mutual Life Association of Australasia Ltd,[90] Redlich J observed:

"Liability for misleading and deceptive conduct by silence under the TPA does not require a duty to speak but calls for an objective assessment of the relevant circumstances to determine whether conduct was misleading or deceptive. Whilst common law and equitable principles may be relevant in assessing whether a contravention of s 52 of the TPA has occurred, they are not determinative. Conduct that is misleading or deceptive may not always involve misrepresentation. The effect of any silence or inaction, and whether it is in contravention of s 52, must be deduced from an examination of the context in which such action or inaction occurred. Silence may be the element which renders the conduct misleading or deceptive upon an objective analysis of all of the circumstances."

[76] Tri-Star makes two complaints about the misleading and deceptive conduct pleading. First, it submits that the Representations are not of future matters but only of Tri-Star's "present opinion". The allegations concerning the absence of reasonable grounds are said by Tri-Star to be irrelevant. Second, Tri-Star submits that there is an absence of a foundation in the pleaded case for "considering APLNG to have held a reasonable expectation that Tri-Star would inform APLNG, not of an existing fact (because APLNG contests the fact of reversion), but of Tri-Star's opinion as to the effect of the [CP payment]"[91].

[77] As to the first complaint, Tri-Star's characterisation of the pleading as involving only a representation of an opinion is incorrect for the reasons already provided. Moreover, the Representations to the effect that Tri-Star "would not contend" that Reversion had occurred or "would not contend" to the effect of any of the Undisclosed Matters are plainly representations as to a future matter.

[78] As to the second complaint, the reasonable expectation is alleged by reference to a series of matters including that the Undisclosed Matters were important matters relevant to the parties' respective rights and obligations and important to APLNG's consideration in deciding whether to approve FID1 or alternatively to approve FID2 and the steps taken thereafter in pursuit of the project. It is alleged (without complaint by Tri-Star) that Tri-Star knew or ought to have known of the importance of the Undisclosed Matters and further knew, as was the fact, that APLNG was unaware of the Undisclosed Matters, proceeding in the belief and on the assumption that reversion had not occurred and in the belief and on the assumption that the CP payment was not characterised as "R" and that there was no existing or ongoing contention by Tri-Star to that effect. Against the background of those pleaded matters, I reject the submission that there is no "foundation in the pleaded case" for the existence of the reasonable expectation.

[79] I decline to strike out the pleaded Representations and the APLNG Assumptions.

[80] In paragraphs 243 and 244 of the pleading, APLNG pleads a case of estoppel by standing by. Estoppel by standing by, also known as estoppel by acquiescence, is a form of proprietary estoppel.

(a) APLNG expended money, time, effort and skill on exploiting developing and improving the Reversionary Interests on the assumption, and believing, that it had ownership of the Reversionary Interests and that reversion had not occurred;

(b) Tri-Star knew of APLNG's assumption and belief and knew of its adverse claim to the Reversionary Interests based on an assertion of the occurrence of reversion but "stood by in silence as to the Undisclosed Matters in the circumstances of [Tri-Star's] knowledge and the reasonable expectation or equitable duty of disclosure of the Undisclosed Matters";

(c) It was unconscionable or inequitable for Tri-Star to maintain silence as to the Undisclosed Matters and otherwise not to assert an adverse title to the Reversionary Interests based upon the occurrence of reversion until the commencement of this proceeding in October 2014 whilst knowing that APLNG was expending money, time, effort and skill on exploiting, developing and improving the Reversionary Interests as part of the project the subject of FID1 and FID2;

(d) Tri-Star by its claims as to the occurrence of reversion is seeking to profit by, or take advantage of or benefit from APLNG's mistakes, or alternatively the APLNG Assumptions which Tri-Star could have prevented by not remaining silent and by promptly asserting an adverse title.

[82] In the premises of those allegations, APLNG asserts that Tri-Star is estopped from claiming the occurrence of reversion by the First Alleged Reversion Date, being no later than 1 November 2008, and from seeking any related relief.

[83] Tri-Star submitted that the pleaded case of proprietary estoppel by standing by "must fail" for two discrete reasons. First, whether reversion had occurred, and hence the existence of any proprietary right, was too uncertain to establish a proprietary estoppel. Secondly, any "standing by" necessarily ceased with the 28 May 2012 Letter. For these two reasons, Tri-Star sought to strike out paragraphs 243, 244 and 245 (insofar as it relies on paragraphs 243) of the pleading.

[84] As to the first reason, Tri-Star submitted that proprietary estoppel by standing by required knowledge of a legal interest or proprietary right. According to that submission, a proprietary estoppel could not arise where the party sought to be estopped does not know that it is the owner. A distinction was to be drawn between knowledge of the existence of a proprietary right which objectively existed and rights which were uncertain or only arguable. Tri-Star submitted that the pleaded case went no further than to assert that Tri-Star knew of its adverse claim to the Reversionary Interests based on an assertion of the occurrence of reversion.

[85] The "foundation stones"[92] of the principle or doctrine of estoppel by acquiescence were laid by Ramsden v Dyson[93] and Willmott v Barber.[94]

[86] In Ramsden v Dyson, Lord Cranworth identified a principle in these terms:

"If a stranger begins to build on my land supposing it to be his own, and I perceiving his mistake, abstain from setting him right, and leave him to persevere in error, a court of equity will not allow me afterwards to assert my title to the land ... It considers that ... it was my duty to be active and to state my adverse title; and that it would be dishonest in me to remain wilfully passive on such an occasion in order afterwards to profit by the mistake which I might have prevented"

[87] In Willmott v Barber, Fry J identified five requirements of estoppel by acquiescence as follows:

"A man is not to be deprived of his legal rights unless he has acted in such a way as would make it fraudulent for him to set up those rights. What, then, are the elements or requisites necessary to constitute fraud of that description? In the first place the plaintiff must have made a mistake as to his legal rights. Secondly, the plaintiff must have expended some money or must have done some act (not necessarily upon the defendant's land) on the faith of his mistaken belief. Thirdly, the defendant, the possessor of the legal right, must know of the existence of his own right which is inconsistent with the right claimed by the plaintiff. If he does not know of it he is in the same position as the plaintiff, and the doctrine of acquiescence if founded upon conduct with a knowledge of your legal rights. Fourthly, the defendant, the possessor of the legal right, must know of the plaintiff's mistaken belief of his rights. If he does not, there is nothing which calls upon him to assert his own rights. Lastly, the defendant, the possessor of the legal right, must have encouraged the plaintiff in his expenditure of money or in the other acts which he has done, either directly or by abstaining from asserting his legal right. Where all these elements exist, there is fraud of such a nature as will entitle the court to restrain the possessor of the legal right from exercising it, but, in my judgment, nothing short of this will do."

[88] Tri-Star referred to Kammins Ballrooms Co Ltd v Zenith Investments,[95] where Lord Diplock said:

"But in contrast to estoppel in the strict sense of the term the party estopped by acquiescence must, at the time of his active or passive encouragement, know of the existence of his legal right and of the other party's mistaken belief in his own inconsistent legal right. It is not enough that he should know of the facts which give rise to his legal right. He must also know that he is entitled to the legal right to which those facts give rise"

[89] This statement appears in a passage in which Lord Diplock referenced Willmott v Barber[96] as authority for "the essential elements of quasi-estoppel by acquiescence". which included the requirement that the possessor of the legal right must know of the existence of his own right which is inconsistent with the right claimed by the plaintiff.

[90] In Taylors Fashions Ltd v Liverpool Trustees Co[97] Oliver J emphasised that the facts of Willmott v Barber involved a case where what was alleged was a waiver by acquiescence. Oliver J described Willmott v Barber as a case of pure acquiescence involving mere silence where what was relied on was a waiver of the landlord's rights by standing by without protest. Oliver J expressed some doubt that the Willmott v Barber requirements are necessary requirements in all cases. Oliver J stated:[98]

"It is suggested in Spencer Bower and Turner, Estoppel by Representation, 3rd ed. (1977), para. 290 that acquiescence, in its strict sense, is merely an instance of estoppel by representation and this derives some support from the judgment of the Court of Appeal in De Bussche v. Alt (1878) 8 Ch.D. 286, 314. If that is a correct analysis then, in a case of mere passivity, it is readily intelligible that there must be shown a duty to speak, protest or interfere which cannot normally arise in the absence of knowledge or at least a suspicion of the true position. Thus for a landowner to stand by while a neighbour lays drains in land which the landowner does not believe that he owns (Armstrong v_. Sheppard & Short Ltd._ [1959] 2 Q.B. 384) or for a remainderman not to protest at a lease by a tenant for life which he believes he has no right to challenge (Svenson v_. Payne_ [1945] HCA 43; (1945) 71 C.L.R. 531) does not create an estoppel. Again, where what is relied on is a waiver by acquiescence, as in Willmott v. Barber itself, the five probanda are no doubt appropriate."

"... the more recent cases indicate, in my judgment, that the application of the Ramsden v Dyson principle (whether you call it proprietary estoppel, estoppel by acquiescence or estoppel by encouragement is really immaterial) requires a much broader approach which is directed at ascertaining whether, in particular circumstances, it would be unconscionable for a party to be permitted to deny that which knowingly or unknowingly he is allowed or encouraged another to assume to his detriment rather than to inquiring whether the circumstances can be fitted within the confines of some pre-conceived formula serving as a universal yardstick for every form of unconscionable behaviour."

[92] In Bluehaven Enterprises Ltd v Tully[99], the Privy Council noted that case law subsequent to Willmott v Barber had reduced the rigidity of Fry J's apparent insistence upon five requirements being established to the letter[100]. The Privy Council referred with approval to Taylor Fashions and relevantly said:[101]

"... Oliver J's key that unlocks the door to the equitable remedy is unconscionable behaviour and although it might be difficult to fashion the key without a representation by the defendant it would not, in principle, necessarily be impossible to do so. Enrichment of A brought about by improvements to A's property made by B otherwise than pursuant to some representation, express or implied, by acquiescence or by encouragement, for which A is responsible would not usually entitle B to an equitable remedy but the reason would be that A's behaviour in refusing to pay for improvements that he had not asked for or encouraged could not, without more, be described as unconscionable."

[93] More recently in Echo v Que[102] Ward CJ observed that some relaxation of the five requirements in Wilmott is discernible in the authorities and noted commentary to the effect that the five requirements may well be necessary in a case of "pure passivity" but may not be applicable to every case of estoppel by acquiescence.

[94] I find that the present case is not able to be described as a case of "pure passivity". APLNG submitted that, for the purposes of this aspect of the strike out application, the real issue was whether the pleading disclosed an arguable basis on which it might be found at the trial that Tri-Star had sufficient knowledge of its rights that its conduct in standing by, having regard to all the circumstances pleaded, was unconscionable. I accept that submission. In my consideration, it is significant that the pleaded circumstances include the allegation that Tri-Star stood by in silence as to the Undisclosed Matters in circumstances of knowledge, and an alleged reasonable expectation or equitable duty of disclosure, of the Undisclosed Matters. When regard is had to the matters pleaded by APLNG, it is also noteworthy that APLNG alleges that Tri-Star had knowledge that reversion had in fact occurred at or around the time of the First Alleged Reversion Date (paragraph 213(a)). That in terms is an allegation that Tri-Star knew that reversion had occurred. Tri-Star makes no complaint about that allegation of knowledge. I accept APLNG's submission that the extent of Tri-Star's knowledge as to whether reversion had occurred is a question to be determined at trial and that the pleaded allegations are sufficient to raise a triable issue as to whether, in all the pleaded circumstances, Tri-Star's knowledge was sufficient to found an estoppel by standing by. Further, even if the pleading did not expressly allege that Tri-Start had knowledge that the reversion Trigger had occurred, a case based on Tri-Star's belief that reversion had occurred would not in my consideration be struck out simply because Tri-Star's condition of mind was characterised as a belief rather than as knowledge. That would, in my consideration, be an entirely contrived and unsatisfactory basis for a strike out, particularly having regard to "the key that unlocks the door to the equitable remedy" being unconscionable behaviour. I accept APLNG's submission that, for the purposes of this aspect of the strike out application, it is not untenable to allege that a party might be estopped from asserting a right by standing by because at the relevant time it held a belief that a right existed rather than knowledge of the existence of that right.[103]

[95] Tri-Star then submitted that an owner does not "stand by" once it has notified the other party of the owner's claim or objection to the other party's conduct. Tri-Star submitted that the 28 May 2012 Letter notified APLNG of its contention that the CP payment should be included in the reversion calculations. For the purposes of this application, I am not prepared to make any finding of fact as to what notification, if any, was conveyed by the 28 May 2012 Letter. In my consideration, such a finding of fact is clearly a matter for trial and should only be made having regard to all of the relevant evidence. I accept APLNG's submission to the effect that whether the 28 May 2012 Letter provided the requisite distinct notice, is a question that falls to be answered by reference to the whole of the relevant circumstances, including subsequent conduct. It is not a question to be answered on a strike out application.

[96] Presently, each side apparently seeks to rely upon the 28 May 2012 Letter for their own forensic purposes. APLNG seeks to rely upon the letter, read with the 6 June 2012 Letter and Tri-Star's failure to respond to that letter, as relevant to its allegation that there was no subsisting or ongoing contention of Tri-Star that the CP payment was characterised as "R" for the Reversion Trigger.[104] Tri-Star seeks to rely upon the 28 May 2012 Letter within the context of this strike out application for the purpose of submitting that the 28 May 2012 Letter, presumably read in isolation from other facts, contained the requisite notification of Tri-Star's claim that reversion had occurred.

[97] Tri-Star's reliance upon the 28 May 2012 Letter appeared to be quite selective. It placed heavy reliance upon the language "... Tri-Star requires that APLNG ... include these proceeds as part of the Revenue in the Reversion Trigger calculations". However, Tri-Star's submissions overlooked that this language was immediately preceded by the words "... in the present circumstances". The preceding words also noted the possibility that APLNG might disagree with the proposition that the CP payment should form part of the Reversion Trigger calculation and asked APLNG to "provide an explanation for its view". The 28 May letter also included language that objectively might suggest it was not intended as notification of Tri-Star's claim. The letter at states that, "on their face", the CP payment and the Sinopec payment "may" be caught by the definition of Revenue. The letter also included an annexure with a schedule which set out Tri-Star's then working interests in relevant tenures and the working interests that Tri-Star "will hold in the tenures once reversion under the Deed ... occurs".

[98] Further, even if for the sake of argument, the 28 May 2012 Letter is assumed to have given distinct notice of Tri-Star's claim, there is a further issue as to whether, in all the broader circumstances pleaded by APLNG, the claim ought to have been reasserted following the 6 June 2012 Letter and whether the fact that it was not reasserted was unconscionable in those broader circumstances. Such an inquiry appears to be countenanced by the approach in Blue Haven.[105] I reject Tri-Star's submission to the effect that Blue Haven is authority for a general proposition which means that Tri-Star was not required to reassert its claim.[106] Rather, it is clear from Blue Haven that whether a claim ought be reasserted, is very much dependent upon the particular circumstances of each case.

[99] Tri-Star's two abovementioned reasons for striking out paragraphs 243, 244 and 245 (to the extent it relies on paragraph 243) have not been made out.

[100] It is not in dispute that the misleading and deceptive conduct and estoppel claims require APLNG to plead and prove a causal connection between the impugned conduct and the alleged detriment or loss and damage. Whilst causation is not a matter specifically identified in r 150 UCPR, the pleading of causation is more generally governed by r 149. Notably r 149 requires a pleading to state all the material facts upon which a party relies (149(b)) and to state specifically any matter that if not stated specifically might take the other party by surprise (149(c)).

[101] In Sedgwick Australia Pty Ltd v JLOC Super Pty Ltd[107], Bond JA[108] identified the following matters of principle:

"..., if causation is an essential element of a pleaded cause of action:

(a) The pleader must plead the material facts which establish the

necessary causal link between the alleged wrongful conduct and

(b) That duty extends to require the pleader to plead the material

facts on which the party relies to establish any counterfactual relied on to establish the requisite causal link.

(c) The pleading so framed, must give rise to a reasonable inference

that the alleged wrongful conduct and the claimed loss stand to each other in the relation of cause and effect.

(d) The entitlement to have the foregoing matters pleaded should be

regarded as an incident of the essential function of pleadings, which is to ensure the basic requirement of procedural fairness that a party should have the opportunity to meet the case put against it."

[102] After outlining those matters of principle, Bond JA observed:[109]

"I interpolate that not every case will require the specific pleading of a counterfactual. The causal link may be obvious. Or a specific counterfactual may not form part of the claimant's case. But, on the other hand, the causal link might not make sense without a pleaded counterfactual. Or the requisite inference of cause and effect might not be able to be drawn without a pleaded counterfactual. Or it might be unfair to the other party not to plead the counterfactual relied on. In such cases a specific pleading of the counterfactual is required."

[103] For its estoppel and misleading and deceptive conduct claims, APLNG accepted that the pleading sought to advance a causal element of detrimental reliance.[110] Under the broad topic of causation, Tri-Star advanced submissions variously directed to the required causal nexus for a pleading in estoppel and for misleading and deceptive conduct, the concept of detrimental reliance and what was styled as a pervading lack of merit in the "causation case".

[104] The fundamental purpose of an estoppel is to protect against detriment.[111] Detriment references the prejudice or disadvantage that the party attempting to set up the estoppel would suffer by reason of his or her change of position in reliance on the representation.[112] A plaintiff bears the legal burden of proof in relation to establishing that reliance led to detriment.[113] The legal burden does not shift.[114]

[105] In the context of common law estoppel, in Thompson v Palmer,[115] Dixon J spoke of the proponent of an estoppel having the onus of establishing that, on the faith of a belief in a representation, an action or inaction was taken which would turn out to be to that person's detriment were the representor permitted to depart from the representation. Hence, the three essential ingredients of estoppel by representation are representation, reliance and detriment.[116]

[106] In the context of equitable estoppel arising by reason of encouragement from a promise, in Kramer v Stone,[117] the plurality[118] identified the third and fourth elements for such an estoppel as follows:

"Thirdly, the promisee must have relied upon the promise by acting or omitting to act in the general manner that would have been expected. In order to establish reliance, it is ordinarily necessary for the promisee to show not merely that the promise was one factor taken into account in motivating the promisee's action or omission but that the promisee would not have acted or omitted to act in the absence of the promise. In other words, it must usually be shown that the promisee's reliance "made a difference to [the promisee] taking the course of action or inaction".

Fourthly, the consequence of the promisee's reliance must be that the promisee will suffer detriment if the promise is not fulfilled, in the sense that the promisee will be left in a worse position, as a consequence of reliance upon the promise, than if the promise had not been made. Unlike the recognition of a gift, or the enforcement of a testamentary promise under a valid will, or the enforcement of a contractual promise, it is the existence of detriment arising from reasonable reliance upon an unfulfilled promise that completes the recognition of the estoppel and moulds the remedial response. As this Court has repeatedly held, "[i]t is not the existence of an unperformed promise that invites the intervention of equity but the conduct of the plaintiff in acting upon the expectation to which it gives rise". Hence, the relief is "moulded accordingly to prevent th[e] detriment". In cases where the detriment suffered by a plaintiff is "a relatively small, readily quantifiable monetary outlay on the faith of the [defendant's] assurances" then, apart from interest, the likely equitable relief ordered will be compensation in the amount of the monetary outlay. By contrast, where the detriment suffered "involves life-changing decisions with irreversible consequences of a profoundly personal nature", the likely equitable relief will be to require fulfilment of the assumption upon which the plaintiff acted, such as by a conveyance of rights, or an assessment of the monetary value of the assumption.

Once these elements are satisfied, it is commonly said that conscience requires that A redress the detriment suffered by B. As has been repeatedly emphasised by this Court, the description of circumstances as unconscionable "is to characterise the result rather than to identify the reasoning that leads to the application of that description".

[107] In Grundt v Great Boulder Pty Gold Mines Ltd,[119] Dixon J referred to the "indispensable' condition that the party asserting the estoppel "have so acted or abstained from acting upon the footing of a state of affairs assumed that he would suffer a detriment if the opposite party were afterwards allowed to set up rights against him inconsistent with the assumption". Dixon J said of a party seeking to establish an estoppel:[120]

"His action or inaction must be such that, if the assumption upon which he proceeded were shown to be wrong and an inconsistent state of affairs were accepted as the foundation of the rights and duties of himself and the opposite party, the consequence would be to make his original act or failure to act a source of prejudice."

[108] That statement reveals that the assessment of detriment requires a comparison between the position the party asserting the estoppel currently occupies and the position the party would have occupied had it not changed its position in reliance on the assumption induced by the representation.[121] The statement also makes clear that the detriment must flow from reliance upon the assumption, when the assumption is to be departed from.[122]

[109] It is not necessary for a person alleging an estoppel to establish that a belief induced by a representation was the sole or predominant cause of the action or inaction. Rather, the belief must be a contributing cause.[123] In that regard, a plaintiff must prove that there was a "sufficient connection between the assumption and the position of detriment".[124] That a belief in a representation "played a part" in identified action was sufficient on the facts of Sidhu v Van Dyke_[125]_ to establish that the representation had contributed to the respondent's conduct. In Sidhu, the plurality [126] referred with approval to a question framed by Robert Goff J namely "whether [a person's] conduct was so influenced by the encouragement or representation ... that it would be unconscionable for the representor thereafter to enforce his strict legal rights,"[127] In Sidhu, Gageler J explained the required connection between assumption and detriment as follows:[128]

"To establish that the belief to which she was induced by the appellant's representations was a contributing cause to the course of action or inaction which she took, the respondent needed to establish more than that she had the belief and took the belief into account when she acted or refrained from acting. She needed to establish that having the belief and taking the belief into account made a difference to her taking the course of action or inaction: that she would not have so acted or refrained from acting if she did not have the belief.

The need for the respondent to establish such a difference stems from what Dixon J described in Grundt ... as the "indispensable" condition that a party asserting an estoppel "must have so acted or abstained from acting upon the footing of the state of affairs assumed" that the party asserting the estoppel "would suffer a detriment if the opposite party were afterwards allowed to set up rights against him inconsistent with the assumption". That is to say, "the real detriment or harm from which the law seeks to give protection is that which would flow from the change of position if the assumption were deserted". There can be no real detriment if the party asserting the estoppel would have been in the same position in any event.

The question of causation is therefore ordinarily appropriately framed, as it was implicitly framed by the primary judge in the present case, as being: "Despite any other contributing factors, would the party seeking to establish the estoppel have adopted a different course (of either action or refraining from action) to that which [the party] did had the relevant assumption not been induced?"

The only authority of this Court potentially in conflict with that approach is Lynch v Stiff. There is a statement in the joint reasons for judgment in that case to the effect that "it is sufficient if [a] party [asserting an estoppel] acts to his prejudice upon a representation made with the intention that it should be so acted upon, though it is not proved that in the absence of the representation he would not have so acted". That statement, however, does not address what is necessary to establish that a party "acts to his prejudice" in the first place. The statement was made in a context where the plaintiff was found to have acted to his prejudice on the basis that his evidence established that he had extended credit "because he believed" in the representation of the defendant."

[110] Hence, there is an important distinction between reliance and detriment. The authorities require an examination of the change of position.[129] That examination does not require an attempt at quantifying all forms or advantage and disadvantage when making the comparison between the relying party's position in fact and their position as it might have been in the absence of reliance on the encouraged expectation.[130] No precise calculation is required and the comparison may involve evaluative judgments as to the possibility of more favourable outcomes in the counterfactual.[131] In a particular case, the question may become whether opportunities have been foregone by reliance which cannot readily be valued but which nevertheless cannot be reflected as carrying only a fanciful or unrealistic prospect that the party encouraged would have been better off. [132]

[111] In Delaforce v Simpson-Cook,[133], in considering a factual situation where, based on an assumption induced by representation, litigation had been abandoned, Allsop P relevantly observed:

"The importance of keeping a party to a representation or encouragement previously made is all the stronger where, as here, the encouragement or representation has been relied upon by a party to abandon a course of conduct that could possibly have led to a different outcome. This can be described in the language of loss of a chance that is not fanciful or unrealistic, or in the language of proceeding thereafter on the basis of a new or changed convention or conventional basis. Such expression of the matter is not different to how Dixon J put the matter in Grundt v Great Boulder Proprietary Gold Mines Ltd [1937] HCA 58; (1937) 59 CLR 641 at 674-675. For instance, if, as here, in reliance upon a representation or encouragement, a court case is abandoned and the representation or encouragement is later sought to be resiled from, the party to whom the representation or encouragement was made and in whom the expectation was raised is left in the position not only of the loss of the entitlement to pursue his or her rights in the case in the past, but also is likely to be in the position of being unable to demonstrate what would, or even may, have happened in the case, it being an alternative, complex and now hypothetical body of human conduct. That the party encouraged cannot show that he or she would have been better off in the posited alternative reality is not fatal to the making out of the estoppel. Indeed, the inability to prove such things reveals a central aspect of the detriment: being left, now, in that position. Of course, if it is self-evident or can be clearly demonstrated that the case was fanciful or otherwise doomed to fail, there may be no real detriment; but that was not the case here."

[112] In AFSL v Hills Industries,[134] the plurality observed that detriment is not a narrow or technical concept and, as long as it is substantial, it need not consist of expenditure of money or other quantifiable financial detriment. The plurality referred to an observation of Robert Walker LJ in Gillett v Holt[135] that the requirement of detriment must be approached as "part of a broad inquiry as to whether repudiation of an assurance is or is not unconscionable in all the circumstances".

[113] In AFSL, Gageler J relevantly said:[136]

"The foundation of an estoppel lying in a change of position to the prejudice of the party asserting the estoppel, the burden of proof lies with that party. The "real detriment or harm" which that party must prove to ground an estoppel can be any "material disadvantage" which would arise from permitting departure from the assumption on the faith of which that party acted or refrained from acting. Material disadvantage must be substantial, but need not be quantifiable in the same way as an award of damages. Material disadvantage can lie in the loss of a legal remedy, or of a "fair chance" of obtaining a commercial or other benefit which "might have [been] obtained by ordinary diligence."

[114] In Q v E,[137] Meagher JA referred to detriment or harm which is sufficiently substantial that it would be unconscionable for the party who gave the assurance to depart from it. His Honour then said:[138]

"There may be cases in which an estoppel is established but the disproportion between detriment and expectation is so great that conscience does not require the party estopped to make good the assurance ... But for the question of relief to arise at all there must be detriment that is sufficiently substantial (or, to use equivalent expressions, real or material) to bind the conscience of the party said to have been estopped".

[115] In E Co v Q,[139] Ward CJ made this observation in relation to estoppel by standing by:

"... the significance, practically speaking, of estoppel by acquiescence is that its existence confirms that there is scope for equity to grant relief, notwithstanding the absence of a representation or promise, in a case where one party seeks to act inconsistently with a belief (concerning real property) adopted by another on which that other party has reasonably relied to his or her detriment to the knowledge of the other party"

[116] In the context of a misleading and deceptive conduct claim for damages under s 82, a plaintiff must prove that the impugned conduct was "a cause", not the sole cause, of the alleged loss.[140] An applicant can only recover compensation for actual loss or damage incurred, as distinct from potential or likely damage.[141] Loss or damage under s 82(1) is "the gist of the action".[142] Causation is a question of fact to be determined by reference to common sense and experience and one upon which policy considerations and value judgments necessarily enter.[143] When deciding that question of fact, the law looks at what influences the actions of parties.[144]

[117] In the context of a cause of action for misleading or deceptive conduct, the High Court has observed that reliance can only be assessed with close attention to all the evidence that bears upon the question being examined.[145] In Sellars v Adelaide Petroleum[146], the plurality,[147] echoing an earlier statement in Wardley, observed that in the context of a misleading and deceptive conduct claim "acts done by the representee in reliance upon the misrepresentations amount to a sufficient connexion to satisfy the concept of causation". The plurality went on to observe that "if those acts result in economical financial loss, it would ordinarily be recoverable" and an applicant is entitled to recover "a sum representing the prejudice or disadvantage [the applicant] has suffered in consequence of his altering his position under the inducement."[148]

[118] The prejudice or disadvantage which the respondents suffered in Sellars was "the loss of the opportunity or chance of securing commercial benefits".[149] The plurality in Sellers recognised a principle which requires that damages for deprivation of a commercial opportunity occurring by reason of misleading or deceptive conduct, be ascertained by reference to the Court's assessment of the prospects of success of that opportunity had it been pursued.[150] The plurality went on to state:[151]

"On the other hand, the general standard of proof in civil actions will ordinarily govern the issue of causation and the issue whether the applicant has sustained loss or damage. Hence the applicant must prove on the balance of probabilities that he or she has sustained some loss or damage. However, in a case such as the present, the applicant shows some loss or damage was sustained by demonstrating that the contravening conduct caused the loss of a commercial opportunity which has some value (not being a negligible value), the value being ascertained by reference to the degree of probabilities or possibilities. It is no answer to that way of viewing an applicant's case to say that the commercial opportunity was valueless on the balance of probabilities because to say that is to value the commercial opportunity by reference to a standard of proof which is inapplicable."

[119] In a separate judgment, Brennan J relevantly observed:[152]

"Gates v City Mutual Life Assurance Society Ltd shows that, for the purposes of s 82(1) of the Act, the loss of a mere opportunity to acquire a benefit is not in itself a loss, but the loss of the benefit will be such a loss if the plaintiff proves that he could and would have taken the opportunity and that the benefit would then have been yielded. That is tantamount to saying that the benefit is a loss in respect of which an amount may be recovered if the links in the chain of causation up to the loss of a benefit are proved. In this respect the law under s 82(1) is no different from the law of torts."

[120] Brennan J emphasised that a causal relationship between the loss of an opportunity and a defendant's contravening conduct must be proved before any issue of assessment of the amount of the loss arises.[153] Hence, the loss of a valuable opportunity and the assessment of its amount are logically separate concepts. The balance of probabilities is the standard of proof required to establish both causation and the existence of a loss, though that standard is inappropriate to the assessment of the amount of a loss where the assessment is merely an evaluation of future possibilities.[154]

[121] For the purpose of considering the present strike out complaints about the plea of detrimental reliance, the following core principles can be distilled from the foregoing analysis of authorities:

(a) There is a relevant distinction between reliance and detriment;

(b) Detriment is not a narrow or technical concept and, as long as it is substantial, it need not consist of expenditure of money or other quantifiable financial detriment.

(c) In the context of estoppel by representation, the question of causation is ordinarily appropriately framed as follows: Despite any other contributing factors, would the party seeking to establish the estoppel have adopted a different course (of either action or refraining from action) to that which the party in fact adopted had the relevant assumption not been induced?

(d) The assessment of detriment requires a comparison between the position the party asserting the estoppel currently occupies and the position the party would have occupied had it not changed its position in reliance on the assumption induced by the representation;

(e) With an equitable estoppel arising by reason of encouragement from a promise, to establish reliance, it is ordinarily necessary for the promisee to show not merely that the promise was one factor taken into account in motivating the promisee's action or omission but that the promisee would not have acted or omitted to act in the absence of the promise;

(f) An assessment of detriment involves a comparison between the reality and the posited alternative reality. Whilst no precise calculation or attempt at quantifying all forms of advantage and disadvantage is required by the comparison, a comparison between two positions is required.

(g) With the cause of action for misleading and deceptive conduct, a causal relationship between the loss of an opportunity and a defendant's contravening conduct must be proved before any issue of assessment of the amount of the loss arises.

(h) Damages for deprivation of a commercial opportunity occurring by reason of misleading or deceptive conduct, are ascertained by reference to the Court's assessment of the prospects of success of that opportunity had it been pursued.

(i) The loss of a mere opportunity to acquire a benefit is not in itself a loss. The loss of the benefit will be such a loss if a plaintiff proves according to the balance of probabilities that it could and would have taken the opportunity and that the opportunity had some value. If that onus is discharged, the value is then ascertained by reference to the degree of probabilities or possibilities.

[122] These core principles inform the pleading obligations contained in r 149(b) and (c) of the UCPR.

[123] Tri-Star relied upon what it described as "a point of principle" being a need or requirement to plead "but for causation with respect to the allegations of detrimental reliance for both the estoppel and misleading and deceptive conduct claims". Tri-Star submitted that an allegation of detrimental reliance could only be maintained if a claimant pleaded facts that establish "but for causation"[155] and submitted that a failure to do so "renders the allegations of detrimental reliance to be struck out on the basis that the required causal nexus has not been pleaded".[156] I have been unable to discern any such bald, absolute statement of principle from the authorities. I have preferred to approach the strike out application by reference to the principles pertaining to estoppel and misleading and deceptive conduct claims which I have earlier considered and identified.

[124] In the estoppel context, APLNG accepted that a representation "must .. have informed the relevant change of position".[157] In the misleading or deceptive conduct context, APLNG also appeared to accept that it was required to demonstrate how it would have acted differently had Tri-Star not made the Representations.[158]

[125] Tri-Star's complaints focused upon three sets of allegations of detrimental reliance. First, a series of allegations contained in paragraph 235 of the pleading. Second, a series of allegations contained in paragraphs 249 to 254I of the pleading. Third, a series of allegations contained in paragraphs 256 to 259.

[126] The allegations contained in paragraph 235 are relied upon for the estoppel and misleading and deceptive conduct claims.[159]

[127] The allegations in paragraph 235 are made against the background of earlier allegations in the pleading which, for the purpose of considering the sufficiency of the allegations in paragraph 235, should be taken as established. Those earlier allegations are broadly to the effect that:

(a) the Representations were made;

(b) the Representations induced the APLNG Assumptions;

(c) APLNG believed that:

(a) the CP payment was not R;

(b) the Reversion Trigger had not occurred;

(c) Tri-Star would not contend that the Reversion Trigger had occurred by reason of the CP payment;

(d) Tri-Star made no contention in the nature of the Undisclosed Matters;

(d) The Plaintiff's Conduct induced APLNG's beliefs;

(e) APLNG relied upon the Representations and the belief they were true by:

(a) approving FID1 and FID2;

(b) making agreements and committing expenditure;

(c) committing to improve the Reversionary Tenements; and

(d) implementing the CSG to LNG project the subject of FID1 and FID2;

(f) Tri-Star knew and intended that APLNG was relying upon the Representations and the APLNG Assumptions;

(g) Tri-Star knew that APLNG held the relevant beliefs and permitted and intended APLNG to do so.

[128] As has been noted, the Representations are alleged to have been made by reason of the Plaintiff's Conduct which occurred in the context of APLNG having a particular state of mind or belief. The Plaintiff's Conduct is alleged to have occurred over a period spanning 1 November 2008 and October 2014.

[129] It is convenient to note that, broadly, the Plaintiff's Conduct involves:

(a) Tri-Star not paying or reimbursing APLNG for the payment of expenses and amounts relative to the Reversionary Interests;

(b) Tri-Star not having made elections to participate in proposals for work to be undertaken pursuant to operating agreements in respect of the Reversionary Tenements;

(c) in respect of the Tri-Star cash calls, Tri-Star not having made payments or reimbursed APLNG for payments in amounts relative to the Reversionary Interests;

(d) Tri-Start electing not to participate in gas sale agreements in respect of the Reversionary Tenements;

(e) since the First Alleged Reversion Date, Tri-Star not having sought to contribute to any costs paid as part of the development exploitation or improvement of the Reversionary Interests;

(f) despite knowing that the CP payment was referrable to an opportunity to participate in an integrated CSG to LNG project which involved the use of reversionary CSG produced from the Reversionary Tenements and knowing that reversion had occurred, Tri-Star not disclosing to APLNG the Undisclosed Matters;

(g) Tri-Star failing to meaningfully or positively respond to the statement in the 6 June 2012 letter to the effect that APLNG disagreed with the suggestion that the CP payment came within the definition of R;

(h) since the first alleged Reversion Date, Tri-Star having accepted Overpaid Vendor Royalty and permitted payment of government royalties on the basis that reversion had not occurred;

(i) since the First Alleged reversion Date, Tri-Star having taken no steps to seek an assignment or retransfer from APLNG of any Reversionary Interests.

[130] Against that background, the pleading alleges that APLNG will suffer detriment if Tri-Star is permitted to maintain that the CP payment was R and that the Reversion Trigger has occurred or is permitted to resile from the Representations or the position of the APLNG Assumptions or if the Reversion Trigger occurred by no later than the First Alleged Reversion Date or if the whole or part of the CP payment is treated as R.

[131] Paragraph 235 pleads the alleged detriment for the estoppel claims and for the purposes of the misleading and deceptive conduct claims "the loss or damage which APLNG has suffered or will likely suffer".[160]

[132] The allegations in paragraph 235 are broadly as follows:

(a) APLNG has incurred expenditure on exploring developing and improving and otherwise relating to the Reversionary Interests as part of the project the subject of FID1 and FID2 as well as its payment of government royalties and transportation tolls referable to interests that would have reverted if the Reversion Trigger had occurred. APLNG also refers to its payment since the first alleged Reversion Date of the amount of the Overpaid Vendor Royalty. In [247(a)]avoid or mitigate the sums referred to .... having regard to [Tri-Star's] adverse claims of title and assertions as to the occurrence of reversion";

(b) APLNG expended time, effort and skill relating to the Reversionary Interests since the first alleged Reversion Date;

(c) APLNG will have materially less gas available to be provided from the Upstream Tenements and will be exposed to a materially increased risk that it will be called on to meet its obligations to guarantee supply obligations and the obligations of LNG Train Company under separate agreements. APLNG is exposed to other potential risks associated with taking FID1 and FID2 in circumstances where reversion had already occurred and APLNG will not have ownership of the Reversionary Interests.

(d) APLNG is exposed to the claims of Tri-Star in this proceeding on the basis that reversion has occurred by the First Alleged Reversion Date which it lost the opportunity to avoid or mitigate "having regard to [Tri-Star's] adverse claims of title and assertions as to the occurrence of reversion";

(e) APLNG permitted expenditure by other APLNG parties on the basis that reversion had not occurred;

(f) (by paragraph 235[f](i) to (iv) in particular), APLNG has lost the opportunity to obtain benefits and avoid detriments namely opportunities to consider, investigate, and decide whether to take identified actions, including whether to approve FID1 and FID2, commit expenditure and enter into agreements:

(a) "having regard to [Tri-Star's] adverse claims of title and assertions as to the occurrence of reversion and further or alternatively having regard to the true extent of APLNG's interests in the Reversionary Tenements at the time that decision was to be made";

(b) particularly in relation to the approval of FID1 and FID2, whether it should commit expenditure and enter into agreements;

[133] At paragraph 235(h), APLNG then makes this allegation, relevantly, in the premises of paragraphs 235 (f) and (g):

"[235(h)]... notwithstanding that APLNG would not have acted as it has and that APLNG's position would have been different but for the Representations, APLNG's Assumptions or APLNG's beliefs ... in that APLNG would have acted to or alternatively would have sought to avoid, mitigate or manage the risks associated with adverse claims of [Tri-Star] and an assertion of reversion -APLNG is now in the position as part of its detriment of being unable to identify with precision and conclusively demonstrate:

(i) what would or alternatively may have happened in "alternative complex and hypothetical circumstances";

(ii) what the outcome would, or may have been of the investigations assessments and considerations of APLNG a potential alternative investments, projects or transactions that would or may have been available at the time of proving FID1 and FID2 and thereafter;

(iii) the best alternative position that would have been adopted and then implemented;

(iv) what measures or steps would have been implemented to avoid, mitigate or manage the risks.

having regard to [Tri-Star's] adverse claims of title to the Reversionary Interests and assertions as to the occurrence of reversion".

[134] Finally, at paragraph 235(i), APLNG alleges that since the First Alleged Reversion Date "having regard to the plaintiff's adverse claims of title and assertions as to the occurrence of reversion", APLNG lost the opportunity to consider requiring and to then require Tri-Star "consistent with [Tri-Star's] claim of adverse title and assertions of reversion" to elect whether or not to participate in proposals for work ... related to the Reversionary Tenements pursuant to the operating agreements applicable to the Reversionary Tenements and to pay the proportionate expenditure upon such participation.

[135] The counterfactual apparently proceeds on the basis that, in the posited alternative reality, APLNG would have had opportunities which would have involved it been able to have, and having, regard to certain matters namely:

(a) Tri-Star's adverse claims of title and assertions as to the occurrence of reversion;

(b) alternatively, the true extent of APLNG's interests in the Reversionary Tenements.

[136] The expression "Tri-Star's adverse claims of title and assertions as to the occurrence of reversion" is not defined or particularised. The expression is not equated with the Undisclosed Matters. I assume that the reference is intended to be to Tri-Star's claims and assertion about title as ultimately made in this proceeding. The pleading's expression the "true extent of APLNG's interests in the Reversionary Tenements", is also not defined or particularised. Given the adoption of this expression in the posited alternative reality, it would seem to reference a situation in which Tri-Star's adverse claims of title and assertions as to the occurrence of reversion are taken to be true and correct.

[137] These allegations about the matters to which APLNG would have been able to have regard, appear to be of fundamental importance to the counterclaim. For the purposes of the estoppel claims, they underpin the required comparison between the reality and the posited alternative reality. For the purposes of the misleading and deceptive conduct claims, they are central to the causal relationship between the alleged lost opportunities and the contravening conduct. Yet the pleading does not plead the material facts from which it might be found, directly or by way of inference, that, in the counterfactual situation, APLNG would have become aware of, so as to have regard to, Tri-Star's adverse claims of title and assertions as to the occurrence of reversion. Nor does it plead the material facts from which it might be found, directly or by way of inference, that, in the counterfactual situation, APLNG would have become aware of, so as to have regard to, the true extent of APLNG's interests in the Reversionary Tenements.

[138] The Representations and APLNG Assumptions are alleged to have been made and induced by the Plaintiff's Conduct, which occurred over a period of years and in a context in which APLNG held certain beliefs and was unaware of the Undisclosed Matters. The claims of detriment as presently pleaded are directed, inter alia, to lost opportunities to obtain benefits and avoid detriments by having regard to Tri-Star's adverse claims of title and assertions as to the occurrence of reversion or, alternatively, the true extent of APLNG's interests in the Reversionary Tenements. Necessarily, those hypothetical opportunities must involve a factual situation in which the Representations were not made and the APLNG Assumptions not induced.

[139] That the Representations were not made does not however sufficiently identify the material facts which comprise the proposed counterfactual. In particular:

(a) It should not be lost sight of that, in its pleading of the events which in fact occurred, APLNG's case proceeds on the basis that APLNG's lawyers statements in the 28 May 2012 Letter to the effect that the CP payment "may be caught by the definition of Revenue" and "should be included in Reversion Trigger calculations" are apparently not to be regarded as an adverse claim of title or as an assertion as to reversion.

(b) I accept Tri-Star's submission to the effect that the pleaded allegations that APLNG has been deprived of an opportunity to have regard to Tri-Star's adverse claims of title and assertions as to the occurrence of reversion is "unparticularised to the point of being meaningless"[162];

(c) However, this is not just a point about particulars. Assuming that Tri-Star's adverse claims of title and assertions as to reversion are essentially its claims and assertions about title and reversion as made in this proceeding, the pleading does not plead material facts namely the acts, conduct or events that would have occurred in the posited alternative reality by which APLNG would have become aware of, and had regard to, Tri-Star's adverse claims of title and assertions as to reversion. The timing of those acts, conduct or events may be expected to be important for informing proper disclosure, the identification of witnesses and to prevent surprise.

(d) The pleading also does not plead the material facts namely the acts, conduct or events that would have occurred in the posited alternative reality by which APLNG would have become aware of, and had regard to, the true extent of APLNG's interests in the Reversionary Tenements. The timing of those acts, conduct or events may also be expected to be important for informing proper disclosure, the identification of witnesses and to prevent surprise;

(e) Whilst the pleading alleges that Tri-Star knew or ought to have known that reversion had occurred by the First Alleged Reversion Date or further or alternatively held the belief that reversion had occurred by the First Alleged Reversion Date or before 28 July 2011 or before 4 July 2012,[163] there are no allegations as to whether and when any such knowledge or belief would have been disclosed or communicated by Tri-Star to APLNG in the posited alternative reality;

[140] In my consideration, paragraph 135 fails to meet the pleading requirements contained in Rule 149(1)(b) and (c). To comply with rule 149 (1)(b) and (c), APLNG should plead the material facts which reveal the counterfactual of the posited alternative reality. The pleading as it presently stands does not plead those material facts. To enable a comparison between the reality and the posited alternative reality it is essential that the pleading properly pleads the counterfactual based as it is on the fundamental propositions that in the posited alternative reality a different position would have pertained because APLNG would have been able to have, and would have had, regard to Tri-Star's adverse claims of title and assertions as to the occurrence of reversion or alternatively, the true extent of APLNG's interests in the Reversionary Tenements. This is particularly necessary because, in the actual reality or the events which have occurred, APLNG still maintains in this litigation, despite being confronted with Tri-Star's pleaded claims, that reversion has not occurred.

[141] The lack of clarity about the counterfactual was reinforced by oral submissions made by APLNG. The following oral submissions were made:

(a) "You could imagine a circumstance in which payments are made by Tri-Star but they're immediately made under protest or they refuse to receive the sums that are predicated on reversion not having occurred. Now if that happens, responsible sophisticated counterparties have to sit down and say 'We need to resolve this. You're paying under protest. We've got a giant liability on our books or you're not receiving the payments we're trying to remit to you. So our counterfactual world ... is had you said that a whole different sphere of possibilities might have arisen. We wouldn't necessarily have accepted that reversion had occurred; we might have. We might have negotiated a purchase of gas and some other settlement. We might have negotiated with other third parties ... And it is significant that we do not plead that we would not have accepted that reversion had occurred. And in any event that's a question that would have to be looked at over time. Circumstances change"[165]

(b) "APLNG's case is that it would have acted differently not on the basis that reversion had in fact occurred but because the risk that it was wrong about that having occurred and the potential impact about the loss of that gas would've had on the proposed CSG to LNG project was just too great such that it would have to have acted to avoid or mitigate the risk".[166]

[142] In my consideration, the posited alternative reality should make clear what conduct would have been engaged in by Tri-Star, what conduct would have been engaged in by APLNG and how APLNG would have addressed the issue of reversion having occurred by reason of the CP payment. If it is the case that in the counterfactual, APLNG would not have accepted that reversion had occurred, that should be made clear by the pleading. The same is true if it is to be alleged that APLNG would have accepted that reversion had occurred. The counterfactual events could be expected to be significantly different depending upon whether APLNG accepted, or did not accept, the event of reversion. These matters should not be left to speculation or conjecture.

[143] There are further problems with paragraph 235 by reason of the terms of paragraph 235(h). That paragraph pleads in terms that "notwithstanding that APLNG would not have acted as it has" and that "APLNG's position would have been different but for the Representations, APLNG's Assumptions or APLNG's beliefs ... in that APLNG would have acted to or alternatively would have sought to avoid, mitigate or manage the risks associated with adverse claims of [Tri-Star] and an assertion of reversion", APLNG is unable to "identify with precision and conclusively demonstrate":

(a) what would or alternatively may have happened in alternative complex and hypothetical circumstances having regard to [Tri-Star's] adverse claims of title to the Reversionary Interests and assertions as to the occurrence of reversion;

(b) what the outcome would, or may have been of the investigations assessments and considerations of APLNG a potential alternative investments, projects or transactions that would or may have been available at the time of proving FID1 and FID2 and thereafter having regard to [Tri-Star's] adverse claims of title to the Reversionary Interests and assertions as to the occurrence of reversion;

(c) the best alternative position that would have been adopted and then implemented having regard to [Tri-Star's] adverse claims of title to the Reversionary Interests and assertions as to the occurrence of reversion;

(d) what measures or steps would have been implemented to avoid, mitigate or manage the risks having regard to [Tri-Star's] adverse claims of title to the Reversionary Interests and assertions as to the occurrence of reversion.

[144] To the extent that paragraph 235(h) is relied upon in respect of the estoppel claims, APLNG's submissions expressly stated that this subparagraph "is premised on the fact that, given the complex nature of the project, APLNG does not know what it would have done but alleges that it would have done something..."[167] The language of paragraph 235(h) appears to draw heavily upon the statement of Alsop P in Delaforce[168]. Alsop P's statement was introduced by first emphasising the importance of keeping a party to a representation or encouragement where "the encouragement or representation has been relied upon by a party to abandon a course of conduct that could possibly have led to a different outcome". On the facts in Delaforce, the abandoned course of conduct involved a court case having in fact been abandoned in reliance on a representation. That is, in terms of the required posited alternative reality, the course of conduct which had been abandoned was apparent and clear. The real issue in Delaforce was whether it could be said to be fanciful or unrealistic that the pursuit of the litigation could possibly have led to a different outcome. In this case, on the face of the pleading there is a lack of clarity about what course of conduct was in fact abandoned or not pursued so as to lead to any change of position. In my consideration that inquiry is necessarily anterior to any subsequent consideration as to whether the pursuit of the abandoned course of conduct could possibly have led to a different outcome. Paragraph 235(h) of the pleading appears to focus on the later, but not the former, enquiry.

[145] There is a further issue to the extent that paragraph 235(h) is sought to be relied upon for the purposes of the misleading and deceptive conduct claims as "the loss or damage which APLNG has suffered or will likely suffer".[169] For the purposes of a damages claim under s 82, the loss of a benefit will be a relevant loss if a plaintiff proves according to the balance of probabilities that it could and would have taken the opportunity and that the opportunity had some value. The plurality in Sellers recognised a principle which requires that damages for deprivation of a commercial opportunity occurring by reason of misleading or deceptive conduct, be ascertained by reference to the Court's assessment of the prospects of success of that opportunity had it been pursued.[170] Brennan J spoke in terms of the loss of a benefit being a loss "if the plaintiff proves that he could and would have taken the opportunity".

[146] The words "with precision and conclusively demonstrate" are in my view apt to distract from the reality that the pleading in paragraph 235, by reason of paragraph 235(h), has not actually identified an opportunity of some value which APLNG would have pursued. APLNG bears the onus of proving on the balance of probabilities the existence of an opportunity, or opportunities of some value, which would have been pursued. In my consideration, these pleas are insufficient to identify such an opportunity. They are essentially speculative and to the extent that no material facts are pleaded supporting a finding as to why any of these opportunities would have been pursued in the posited alternative reality, they are technically embarrassing and do not disclose a reasonable cause of action under s 82.

[147] In relation to paragraph 235(ca) there was ultimately no issue that the paragraph as presently pleaded was embarrassing and lacked particulars. The paragraph refers to APLNG being exposed to "other potential risks associated with taking FID1 and FID2 in circumstances where reversion had already occurred and where APLNG will not have ownership of the Reversionary Interests that have reverted". The particulars of that allegation are to the effect that the "nature of the commercial and legal risks are related to project finance and warranties that APLNG has given". Tri-Star had previously sought particulars. APLNG responded in its written submission to the effect that particulars would be provided. It was not apparent why APLNG has not provided particulars of this allegation, which apparently concern matters within its own knowledge, at any time prior to the hearing of the strike out application. The allegation is clearly lacking in particulars and is amenable to striking out.

[148] Beyond the lost opportunities identified in paragraph 235, the paragraph also refers to acts of reliance such as payments of expenditure, expending time, effort and skill exploiting, developing and improving the Reversionary Tenements and the entering into of agreements.[171] I do not regard these allegations, by themselves, as a sufficient plea of detriment. Rather the real detriment appears to be intrinsically linked to the allegation that APLNG lost the opportunity to "avoid or mitigate" those payments, expenditures and dealings "having regard to the plaintiffs' adverse claims of title and assertions as to the occurrence of reversion".[172] Without the proper pleading of a counterfactual in respect of those opportunities, it is not possible to discern whether these payments or expenditures or the entry into the agreements reflect a change of position from the reality which has occurred. There is no relevant detriment discernible for the purpose of paragraph 243(a) of the estoppel by standing by plea. Paragraphs 243(a) and 244 should be struck out with leave to replead.

[149] Paragraphs 249 to 254I of the pleading concern the loss of opportunities to develop the LNG project differently. These paragraphs of the pleading are only relevant to the claims of misleading or deceptive conduct. The paragraphs extend over a large number of pages of the pleading. Tri-Star sought to summarise those paragraphs in the following manner:

(a) had Tri-Star not engaged in the contraventions, APLNG "would have" had an opportunity to develop the project the subject of FID1 and FID2 by acquiring an interest in or access to alternative sources of CSG or alternative commercial arrangements to acquire CSG;

(b) had Tri-Star not engaged in the contraventions, APLNG "would have sought" to acquire an interest in or access to alternative sources of CSG, or alternative arrangements to acquire CSG in amounts to replenish all or part of "that which had been lost by reason of reversion having occurred ("Replenished Gas")" in order to commence and then continue with the project the subject of FID1 and FID2 or a CSG to LNG project of a different scope or size;

(c) had Tri-Star ceased the contraventions prior to FID1 or alternatively FID2, APLNG would have been faced with "a substantial risk" that it may not have sufficient gas reserves to support the taking of FID1 and FID2 and "a substantial risk" that it would have been unable to secure the commercial agreements and arrangements necessary in order to commit to and then undertake a CSG to LNG project based upon 2 x 4.5 mtpa LNG Trains;

(d) post FID1 and FID2, had Tri-Star "ceased the contraventions", APLNG's commercial option "would have been to seek to require Replenished Gas";

(e) but for Tri-Star's contraventions and at all times prior to FID1, substantial commencement and implementation of FID1, to FID2 or substantial commencement and implementation of FID2, APLNG "would have" investigated, assessed and considered the options that would or may have been available to it to enable it to acquire Replenished Gas or otherwise commence or continue with the CSG to LNG Project the subject of FID1 and FID2;

(f) the investigations assessments and consideration which APLNG would have undertaken "are those pleaded in sub-paragraphs 235(f)(i) to (xiii) above"[173];

(g) by that process of investigation, assessment and consideration, APLNG would have identified four options described as Options 1 to 4;

(h) APLNG would have proceeded to assess, select and pursue the option which provided the best financial outcome for the APLNG parties;

(i) had Tri-Star not contravened the TPA and ACL as alleged, APLNG would have pursued one of Options 1 to 4 and would have identified, pursued and implemented, the option that it determined was its best option;

(a) Option 1: to acquire from Tri-Star, CSG produced from the Upstream Tenements in a quantity at least ### to Tri-Star's entitlement to any CSG produced, or to be produced from the Reversionary Interests;

(b) Option 2: to acquire CSG from third party producers and sellers of gas and to accelerate the development of APLNG's tenements, to provide APLNG with sufficient Replenished Gas to continue the project the subject of FID 1 and FID 2;

(c) Option 3: to acquire CSG from third party producers and sellers of gas and to accelerate the development of APLNG's tenements, to provide APLNG with sufficient Replenished Gas to continue a smaller LNG;

(d) Option 4: to acquire (by acquiring its shares) another CSG producer and to acquire CSG from third party producers and sellers of gas, to provide APLNG with sufficient Replenished Gas to continue the project the subject of FID 1 and FID 2.

[151] Beyond the identification of the four options the pleading then describes how, applying the process of investigations, assessments and consideration described as "those pleaded in sub-paragraphs 235(f)(i) to (xiii) above", the alternative options would have been to develop the project the subject of FID1 or FID2 or a smaller project.

[152] The critically important paragraphs are paragraphs 249 to 250B because those paragraphs constitute the basis for the allegations that APLNG, by reason of the contravening conduct or the cessation of the contravening conduct, suffered the loss of valuable commercial opportunities. To the extent that these paragraphs rely upon paragraphs 235(f)(i) to (xiii) of the pleading, which they plainly do, they suffer from the same pleading deficiencies which have already been identified in the specific context of paragraph 235.

[153] Tri-Star made a submission to the effect that the pleading "necessarily involves the proposition that if Tri-Star had told APLNG its view that reversion had occurred, APLNG would have accepted that reversion had occurred". After identifying that proposition, said to be implicit in the pleading, Tri-Star emphasised that an allegation reflecting that proposition was not actually pleaded and, instead, APLNG elsewhere in the pleading repeatedly denies that reversion has occurred. Tri-Star submitted that paragraphs 249 to 251D of the pleading ought to be struck out because they were said to be based upon an allegation "which is not only not made but denied".

[154] Tri-Star referred to various paragraphs of the presently pleaded case on causation to make good its submission that APLNG implicitly contends that it would have accepted that reversion had occurred in the posited alternative reality. Tri-Star referenced the following contentions in the pleading:

(a) APLNG "would have sought to acquire an interest in or access to alternative sources of CSG ... in amounts to replenish all or part of that which had been lost by reason of reversion having occurred";

(b) in respect of Option 1, the option "to acquire from [Tri-Star] CSG produced from the Upstream Tenements in a quantity at least equal to [Tri-Star's] entitlement to any CSG produced or to be produced from the Reversionary Interests (it being noteworthy that at least some of the Upstream Tenements are Reversionary Tenements)[174];

(c) in respect of Option 1, APLNG would have secured an offer to it from Tri-Star for the purchase of Replenished Gas;

(d) in the context of Option 1, it would have been in Tri-Star's commercial interest to "negotiate, agree and execute an Option 1 Replenish Gas GSA in order to avoid risk and 2 achieve the development, exploitation and monetisation of the reversionary CSG if reversion had occurred;

(e) in the context of Option 2, APLNG would have been able to acquire gas from the market because the lifting and supply of Tri-Star's reversionary CSG would have correspondingly increased the volume of gas in the domestic market which would have freed up market supply of CSG from other gas producers and sellers;

(f) in case of any of the four options, had any such option been pursued, APLNG would not have been liable to Tri-Star for damages because APLNG would not have used any CSG referable to the interests that had reverted.

[155] There is considerable force in Tri-Star's submission that, at least in some respects, it is necessarily implicit in the counterfactual, that in the identification, consideration and pursuit of any of the four options, particularly Option 1, APLNG would have recognised that reversion had occurred as contended for by Tri-Star in this proceeding. Such an important allegation of fact should not be left to inference or conjecture, particularly as, in the actual reality, APLNG continues to deny that reversion has occurred. The lingering uncertainty about APLNG's true case as to the nature and extent of any regard it would have had to Tri-Star's adverse claims of title and assertions as to the occurrence of reversion and how any such regard would have affected APLNG's decision making and conduct, is a direct product of the pleading's failure to plead the material facts relevant to the posited alternative reality. On these important matters, the pleading is at best unclear but at worst conceals material facts which should be pleaded to avoid surprise, inform disclosure and the preparation of evidence.

[156] There are further problems with paragraphs 249 to 250B.

(a) To the extent that it is alleged that had Tri-Star not engaged in the contraventions APLNG "would have" had an opportunity to develop the project the subject of FID1 and FID2 by acquiring an interest in or access to alternative sources of CSG or alternative commercial arrangements to acquire CSG, no material facts are pleaded to support such a finding either directly or by way of inference.

(b) Similarly, to the extent that it is alleged that had Tri-Star not engaged in the contraventions, APLNG "would have sought" to acquire an interest in or access to alternative sources of CSG or alternative arrangements to acquire Replenished Gas, no material facts are pleaded to support a finding directly or by way of inference that APLNG would have so acted.

(c) The expression had Tri-Star "ceased the contraventions" is technically embarrassing. Given the diverse conduct said to have involved the Plaintiff's Conduct, it is unclear whether the expression "ceased the contraventions" is simply meant to convey that none of the plaintiff's conduct would thereafter have occurred or only some of that conduct would have ceased. The allegation needs to be clarified. For example, if the contraventions ceased, does that mean the Undisclosed Matters would have been disclosed and if so, when?

(d) Further, in circumstances where the contravening conduct is posited as ceasing, APLNG is alleged to have been faced with "a substantial risk" that it might not have sufficient gas reserves or might be unable to secure commercial agreements and arrangements. The facts underpinning the apparent "substantial risk" have not been pleaded.

(e) It is also unclear how the prospect of a "substantial risk" sits alongside allegations earlier made in paragraph 235 to the effect that in the posited alternative reality, APLNG would have had regard to "the true extent of APLNG's interest in the Reversionary Tenements".

[157] Further, in my consideration paragraphs 235(g), 250B and 251D are inconsistent with paragraph 235(h) of the pleading:

(a) Paragraph 250B proceeds on the basis that as a result of the investigations, assessments and consideration which APLNG would have undertaken as described in sub-paragraphs 235(f)(i) to (xiii), APLNG "would have identified" Options 1 to 4 which are described as options which were available to it.

(b) Paragraph 235(g) earlier "relies on the options pleaded in paragraph 250B".

(c) Paragraph 251D later alleges that APLNG would have selected and pursued and implemented one of Options 1 to 4 which it would have determined as the best option "according to the process pleaded in paragraph 250A", being a process, which involved the investigations, assessments and consideration which APLNG would have undertaken in sub-paragraphs 235(f)(i) to (xiii).

(d) Paragraph 235(h) alleges that APLNG is "unable to identify with precision and conclusively demonstrate what would, or alternatively may, have happened, what the outcome would or may have been of the investigations, assessments and considerations which APLNG would have undertaken in sub-paragraphs 235(f)(i) to (xiii), the best alternative position that would have been adopted and then implemented and what measures or steps would have been implemented to avoid, mitigate or manage the risk.

(e) Paragraph 235(h) is materially inconsistent with paragraphs 235(g), 250B and 251D which effectively allege that, as a result of the same investigations, assessments and considerations there would have been identified four commercially valuable options, one of which would in fact have been pursued.

[158] Tri-Star made a series of complaints about paragraphs 252 to 254I of the pleading which were ancillary to its more substantive complaints about the pleading of the counterfactual leading to Options 1 to 4 as contained in paragraphs 249 to 251D. Tri-Star submitted that paragraphs 252 to 254I were dependent upon paragraphs 249 to 251D and could not be maintained in the pleading absent those prior paragraphs. I accept that submission. Further, paragraphs 252 to 254I appeared, in substantial part, to be more relevant to the valuation or assessment of the alleged lost opportunities rather than to the anterior issue of causation. Many of the complaints made by Tri-Star in respect of paragraphs 252 to 254I were complaints that might be expected to be dealt with by way of the provision of particulars or which might be clarified after further interlocutory steps. I have not found it necessary to deal with the particular merits of Tri-Star's ancillary complaints about paragraphs 252 to 254I. It may also be noted that the content of paragraphs 252 to 254I might change depending upon the content of any reformulated allegations in relation to the pleading of the counterfactual case;

[159] In this context, there is one matter which I felt it appropriate to express a concluded view about. Paragraph 254F(a)(iv) claims as a head of loss "the diminution in the value of shares that APLNG holds .... in the APLNG parties".

[160] Tri-Star submitted that this claim is not sustainable because of what it described as the reflective loss principle, being a principle to the effect that a shareholder cannot recover a sum equal to the diminution in the market value of its shares or equal to the likely diminution in dividend because such a loss is merely a reflection of the loss suffered by the company.[175] The principle applies where each of the company and its shareholders has a cause of action.[176] Tri-Star submitted that according to the pleading each of the APLNG parties whose share prices are alleged to have been diminished claimed to have a cause of action and, in consequence, paragraph 254F(a)(iv) was amenable to striking out.

[161] APLNG acknowledged that the subsidiaries' claims rely on the question whether or not a third party can relevantly claim damages for detriment suffered where a representee relies upon a representation. That is, the pleading alleges that APLNG relied on the representations, but a consequence of that reliance was that the subsidiaries suffered a loss. APLNG submitted that there are two intermediate appellate court authorities relevant to considering whether indirect causation is available[177]. One line of authority supports a submission that indirect causation is available if there has been some reliance within a chain of causation or misleading conduct and the claimant suffered loss because of that misleading conduct. Another line of authority is to the effect that indirect causation can only be establish if the claimant's own conduct or act of forbearance forms a link in the causal chain, if that claim in itself relied on the misleading conduct.

[162] APLNG submitted that the paragraph was not amenable to striking out essentially for these reasons. Reflective loss will not bar a parent company from recovering for the diminution in value of its shareholders in its subsidiaries where those subsidiaries have suffered loss but do not themselves have claims. There is uncertainty over whether or not the subsidiaries in this case will be found at the conclusion of the trial to have their own claims either by reason of the application of legal principle or findings of fact to be made by reference to the evidence. I accept APLNG's submissions in relation to this matter and consider that the determination of what might be described as the 'reflective loss issue' is not a strike out point.

[163] Paragraphs 256 to 259 are expressed to be in the alternative to paragraphs 249 to 255. Paragraphs 256 to 259 concern APLNG's alleged loss of a valuable opportunity to compel what are styled as "the Counterfactual Elections". APLNG pleads that but for the impugned conduct, it "would have" on an ongoing basis from the alleged Reversion Date put the owner of the Retained Interests to elections as to whether or not to participate in proposals for work related to the Reversionary Tenements pursuant to the applicable operating agreements. That opportunity is alleged to have been valuable because upon being put to the Counterfactual Elections, the owner of the Retained Interests would either have elected to participate or not participate in the proposals for work. In the former case, the owner of the Retained Interests would have been obliged to pay expenses relating to the development of the Retained Interests. In the latter case, the owner of the Retained Interests would have forfeited the working interests the subject of the Retained Interests and APLNG would have become the beneficial owner of all or of part of the forfeited Retained Interests. It is also alleged that APLNG would not have paid the Overpaid Vendor Royalty. Tri- Star submits that APLNG "could only have put Tri-Star to such elections and not paid the Vendor Royalty if it had recognised that reversion had occurred and transferred legal title in the Retained Interests to Tri-Star".

[164] The pleading does not plead any of the material facts from which it might be found directly or by way of inference that APLNG "would have" on an ongoing basis acted in the manner alleged by paragraph 256(a). The material facts underpinning the counterfactual are not pleaded. The allegation of causation as contained in paragraph 257 is in the form of a conclusion or mere assertion and, in its present form, is apt to take Tri-Star by surprise. It also appears implicit in the premise of the Counterfactual Elections that APLNG would have accepted that reversion had occurred such that ownership of the Retained Interests had passed to the party being put to the election. Again, if this is the premise of the case it should be clearly pleaded and not left to inference or speculation.

[165] On the assumption that the Representations were made, at least up until 28 May 2012, Tri-Star made submissions in terms that the causation case was "hopeless". Tri-Star submitted that APLNG has no "reasonable prospect" of establishing that it in any way relied upon the Representations or that, had Tri-Star revealed earlier its contention that the CP payment had caused reversion under the 2002 Deed to occur on 1 November 2008, APLNG would have acted any differently to the way in which it in fact acted. In the context of that submission, Tri-Star submitted that it was "apparent that the estoppel and misleading and deceptive conduct claims are ... an invention that defies reality". That submission was developed by reference to further contentions to the effect that it was said to have been "inconceivable" that APLNG did not take its own legal advice and form its own view as to whether the CP Payment was "R" before approving FID1 and FID2 and otherwise progressing the LNG project. It was said to have been "vanishingly unlikely" that the views of Tri-Star on this issue, or Tri-Star's intent to claim reversion had occurred, would have influenced APLNG's views or actions at all. Tri-Star made reference to various parts of the evidence which it relied upon in support of its application. That evidence suggested that at a point in time prior to 19 August 2008, APLNG's holding company had obtained a silk's opinion regarding the relevance of the CP payment to reversion under the 2002 Deed. It was submitted that the evidence also established that APLNG's view had always been and remained that the CP payment was not relevant to reversion under the 2002 Deed. That view was said to have been formed in circumstances where APLNG regarded the occurrence of reversion under the 2002 Deed as potentially having significant consequences for the LNP project. Having regard to the magnitude of the LNP project and APLNG's assessment of the significance of the risk of reversion, Tri-Star submitted that it was "to be expected that APLNG relied on its own assessment as to the operation of the 2002 Deed and was not and would not be, influenced by any views Tri-Star may or may not have held".

[166] These submissions proceeded on the basis that, without the benefit of all the evidence, it was possible to form a concluded view on this application that the causation case was relevantly fanciful and had no real prospect of success. A principal difficulty with these submissions is that Tri-Star urges the court to strike out a causation case as "hopeless" in circumstances where the counterfactual has not been properly pleaded or exposed for scrutiny. Another difficulty is that these submissions invited the Court to look beyond the pleaded facts, not assuming their truth for the purposes of the strike out application, and to cherry pick some of the disclosure and evidence which might be adduced at the trial for the purpose of pre-empting the findings which might be made at the end of a trial after all of the evidence had been adduced and considered. Such an approach is not orthodox and is not warranted in the present circumstances.

[167] For the reasons I have provided paragraphs 235, 243(a) and 244, 249 to 254I and 256 to 259 should be struck out with leave to replead. There should be leave to replead because the striking out proceeds on the basis that the pleading presently does not plead facts or pleads inconsistent facts. The striking out does not proceed on the basis that the facts pleaded are relevantly fanciful or have no real prospects of success.

[168] Tri-Star sought to strike out APLNG's unjust enrichment pleading by reference to three contentions.

[169] The first contention was to the effect that, as a matter of pleading, no independent restitutionary claim based on mistake was available, absent APLNG making out its claim as to estoppel by standing by, which Tri-Star submitted it could not make out and should be struck out. Tri-Star submitted that APLNG's claim in unjust enrichment was based on the same premises as its claim of estoppel by standing by. In that regard, I accept APLNG's submission that its unjust enrichment claim concerns expenditure which, at least in part, extends beyond expenditure on the Reversionary Interests themselves. Further, APLNG marshalled authority[178] which indicated that, on the facts of particular cases, restitutionary awards have been allowed despite claims of estoppel, including estoppel by standing by, failing. It is also noteworthy that whilst I have found that the detrimental reliance aspect of the estoppel by standing by plea is presently non-compliant with the pleading rules and amenable to striking out, Tri-Star's other complaints about the availability of the estoppel were not made good. Taking all of these matters into account, the unjust enrichment claim should not be struck on the basis of Tri-Star's first contention.

[170] The second contention was to the effect that there was no basis for an allegation that the expenditure of which APLNG claims restitution was caused by the alleged mistake because APLNG has not alleged that it would not have expended the money in any event. This contention seemed to suggest that "but for" causation was a requirement of restitution for mistake. It may be accepted that a claim for restitution for mistake involves establishing that a mistake was causative of the relevant harm.[179] APLNG referenced authority to the effect that the test for causation in mistake cases inquires into "whether the mistake was a reason for the enrichment".[180] In Priestley v Priestley,[181] White J applied a similar test for causation to the mistake claim as was applied to the claim for estoppel by standing by. In my consideration, there is a debatable question of law as to whether the law requires "but for" causation in all cases involving a restitutionary claim for mistake. The answer to that question may depend on the factual context and should not be determined at the stage of a strike out application.

[171] The third contention was to the effect that much of the expenditure occurred after the 28 May 2012 Letter and that, in those circumstances, APLNG could not have been mistaken. Again, essentially for reasons I have earlier expressed, I am not prepared to make any findings of fact in relation to the necessary effect and proper interpretation of the 28 May 2012 Letter.

[172] Tri-Star made three essential complaints in relation to the plea of estoppel by convention. The first involved a contention that APLNG did not in fact adopt the alleged Mutual Assumptions. The second involved the contention that the 28 May 2012 Letter and the 6 June 2012 Letter were inconsistent with any allegation to the effect that Tri-Star had proceeded on the basis of the Mutual Assumptions. I accept APLNG's submission that each of these contentions, at their core, involve factual controversies which are not appropriately decided on a strike out application and should await determination of trial. The third complaint is that the estoppel by convention relies upon paragraph 235 of the pleading to establish that APLNG will suffer detriment if Tri-Star is permitted to resolve or depart from the Mutual Assumptions. I have already expressed reasons for my conclusion that paragraph 235 should be struck out. Accordingly, paragraphs 240(e) and 241 and 242 should be struck out with leave to replead.

[173] Tri-Star raised a variety of discrete complaints about the pleading.

[174] Tri-Star sought to strike out paragraph 81.1(b) because it called in aid the misleading or deceptive conduct and estoppel claims by noting that APLNG had acted in the way alleged "by reason of the facts and matters pleaded below in section J of the counterclaim". According to my earlier reasons, the misleading and deceptive conduct and estoppel claims each suffer from deficiencies in relation to causation and more particularly the pleading of detrimental reliance. Paragraph 81.1(b) should be struck out consistently with my earlier reasons, with leave to replead.

[175] Tri-Star submitted that paragraphs 81.1(c)(ii) and 81.1(d)(i)(D) are necessarily inconsistent. Each paragraph was said to be premised on reversion having occurred. The earlier paragraph was said to allege that gas produced from the Reversionary Tenements had been sold, whereas the latter paragraph was said to allege that Tri- Star's share of the gas had been banked. On my review of these paragraphs, the analysis contained within Tri-Star's submission does not reflect the true nature of the allegations. The earlier paragraph proceeds on the basis that reversion has not occurred (paragraph 81.1(a)) or if reversion has occurred, Tri-Star is estopped from contending that reversion has occurred by reason of the facts and matters pleaded in section J of the counterclaim (81.1(b)). To the extent that paragraph 81.1(c)(ii) relies upon paragraph 81.1(b) to found an estoppel, it is amendable to being struck out because of the current deficiencies in the pleading of detrimental reliance. In the context of reversion having not occurred, the pleading relevantly alleges that APLNG has continued to and was entitled to sell its share of the gas produced from the Reversionary Tenements. The pleading contained in paragraph 81.1(d)(i)(D) proceeds on the basis that if reversion has occurred, which APLNG denies, and in respect of certain Reversionary Tenements the subject of the Texan Operating Agreements, Tri-Star's full net share of gas from those Reversionary Tenements has in fact been banked. The words in paragraph 81.1(c)(ii) "and (b)" should be struck out with leave to replead. Otherwise, I do not apprehend any significant inconsistency that warrants the striking out of the remaining parts of paragraph 81.1(c)(ii) or of paragraph 81.1(d)(i)(D).

[176] Tri-Star submitted that paragraphs 83(g) and (h) of the pleading ought to be struck out because they failed to engage with the initial premise of the counter-factual contained in paragraph 83 of the statement of claim which is to the effect that APLNG would have recognised in a timely way that reversion had occurred and caused Tri- Star to be recorded as a legal owner of the Tenements and Petroleum Leases which form part of the Retained Interests. Had those matters occurred, paragraph 83 contends that Tri-Star would have had an opportunity from about late 2008 to sell the Retained Interests and sought to sell the Retained Interests. Paragraphs 83(g) and (h) of the pleading seek to deny those allegations by reference to how Tri-Star in fact behaved in the events which occurred. The relevance of Tri-Star's actual conduct to any assessment upon how it would have behaved in the counterfactual is properly a matter to be left for determination at the trial. I do not regard this complaint as a pleading point.

[177] Tri-Star sought to strike out paragraph 83.1.1(c)(ii)(A) of the pleading which responds to Tri-Star's allegation that it engaged in negotiations with BG and AGL. The subject paragraph of the pleading merely responds to the allegation about those negotiations and contends that they were engaged in with knowledge as to Tri-Star's contention of reversion and whilst Tri-Star maintained silence as against APLNG as to reversion having occurred. Tri-Star maintains that this allegation is irrelevant and can have "no identifiable impact" on the allegations contained in the statement of claim. That appears to be correct at least in respect of the allegations about the negotiations with BG which are alleged to have occurred between June and September 2008. It would seem having regard to the timing of the alleged negotiations that paragraph 83.1.1(c)(ii)(A) can only have potential relevance to the negotiations with AGL to the extent they occurred after the First Alleged Reversion Date. Paragraphs 83.1.1(c)(ii)(a) should be struck out with leave to replead.

[178] Tri-Star made a similar complaint about paragraph 83.1(b) it appearing to be contended that it was irrelevant for APLNG to make reference to failed negotiations engaged in by Tri-Star to sell its interests because Tri-Star's failure to sell in the actual circumstances which occurred could not support an allegation by APLNG that Tri- Star would not have sold the Retained Interests if APLNG had in a timely way recognised reversion in 2008 and transferred the Retained Interests. I accept APLNG's submission that this submission involves a contestable proposition which should be fairly determined at trial namely the extent to which Tri-Star's actual failures to sell are relevant to assessing the likelihood that it would have sold in the counter-factual situation.

[179] Tri-Star sought to strike out sub-paragraphs 90(b)(v)(A), (B), (C) and (D) and 94(b) of the pleading on the basis that those paragraphs were said to encapsulate the proposition that APLNG had sold Tri-Star's gas and incurred expenses in good faith because APLNG was unaware of Tri-Star's contentions regarding the occurrence of reversion. That position was said to be "false because of the existence of the 28 May 2012 Letter". For the reasons I have already provided in relation to the 28 May 2012 Letter, I am not prepared to make any findings as to its proper interpretation and effect. I decline to strike out these paragraphs of the pleading.

[180] Finally, Tri-Star sought to strike out paragraphs 134(b) and 134(c) of the pleading which concern that defences of laches and acquiescence and of unclean hands. Tri- Star submitted that the "existence of the 28 May letter" meant that allegations of delay in making any contentions about reversion were unsustainable. For the reasons I have already provided in relation to the 28 May 2012 Letter, I am not prepared to make any findings as to its proper interpretation and effect. It was also submitted that if Tri-Star's complaints about the misleading or deceptive conduct and estoppel claims succeeded, these defences ought to be struck out. The defences of laches and acquiescence notoriously involve fact-laden inquiries[182]. The particular pleas in this case extend to matters which are not dependent upon the misleading or deceptive conduct or estoppel claims[183]. I accept APLNG's submissions that the pleading of laches, acquiescence and unclean hands raise real questions which should be determined at trial. I am unable to presently conclude that the defences have no realistic prospect of succeeding. Nor is it appropriate in my mind to determine those kinds of equitable defences on a strike-out application without reference to the facts found at trial[184]

(a) The following paragraphs of the sixth further amended defence and counter claim are struck out with leave to replead:

(a) paragraph 81.1(b);

(b) the words in paragraph 81.1(c)(ii) "and (b)";

(c) paragraph 83.1.1(c)(ii)(a);

(d) paragraph 235;,

(e) paragraphs 240(e), 241 and 242;

(f) Paragraphs 243(a) and 244;

(g) paragraphs 249 to 254I;

(h) paragraphs 256 to 259;

(b) I will hear the parties as to costs.

[1] Tri-Star Petroleum Company v Australia Pacific LNG Pty Ltd (formerly Oil Company of Australia Limited) & Anor [2023] QSC 83 at [2].

[2] [1964] HCA 69; (1964) 112 CLR 125 at 129-130.

[4] [1986] AC 368 at 435-6.

[6] Barclay Mowlem Construction Limited v Dampier Port Authority [2006] WASC 281; (2006) 33 WAR 82 at [7] and [8]; Equititrust Limited (Receivers and Managers Appointed) v Tucker [2019] QSC 248 at [15]

[7] APLNG's Outline of Submissions dated 18 July 2025 ("APLNG's Outline").

[8] Tri-Star's Outline of Submissions dated 30 May 2025 ("Tri-Star's Primary Outline") [6](b), [49], [150], [174] and [175].

[9] Tri-Star's Primary Outline [6](b), [154], [173].

[10] Ibid [6](b), [174] and [175].

[16] Barclay Mowlem Construction Limited v Dampier Port Authority [2006] WASC 281; (2006) 33 WAR 82 at [7] and [8].

[17] Polar Aviation Pty Limited v Civil Aviation Safety Authority (No.4) [2011] FCA 1126; (2011) 203 FCR 293 at [10]; Impiombato v BHP Group Limited (No. 2) [2020] FCA 1720 at [141].

[18] Bakewell v Anchorage Capital (2019) 372 ALR 234 at 359 [40] and [41]

[19] Spencer v The Commonwealth (2010) HCA 28; (2010) 241 CLR 118 at [24].

[20] [2006] HCA 27; (2006) 226 CLR 256 at 275 [46].

[21] Gleeson CJ, Gummow, Hayne and Crennan JJ.

[22] [2000] HCA 41; (2000) 201 CLR 552 at 575-576 [57].

[23] (2010) HCA 28; (2010) 241 CLR 118 at 132 [25].

[24] [2020] VSCA 186; (2020) 61 VR 580 at 594 [35].

[25] Much of this overview has been derived from the reasons of Burns J in Tri-Star Petroleum Company v Australia Pacific LNG Pty Ltd [2023] QSC 83 at [2] to [16].

[41] Tri-Star's Primary Outline [49].

[45] Jorden v Money (1854) 5 HL Cas 185; 10 ER 868; Legione v Hateley [1983] HCA 11; (1983) 152 CLR 406 at 432 and Waltons Stores (Interstate) Ltd v Maher [1988] HCA 7; (1988) 164 CLR 387 at 398, 415, 459.

[46] Kramer v Stone [2024] HCA 48; (2024) 281 CLR 484 at 501-502 [36]- [37].

[56] Tri-Star's Primary Outline [50], [51], [67].

[59] [1933] HCA 61; (1933) 49 CLR 507 at 547.

[60] 183 Eastwood Pty Ltd v Dragon Property Development & Investment Pty Ltd [2023] NSWCA 72 at [131].

[61] [1937] HCA 58; (1937) 59 CLR 641 at 674.

[66] [1952] EWCA Civ 7; [1951] 2 KB 215 at 220.

[67] [1988] HCA 7; (1988) 164 CLR 387 at 420-421.

[68] [2024] HCA 48; (2024) 281 CLR 484.

[69] Gageler CJ, Gordon, Edelman and Beech-Jones JJ.

[70] [2024] HCA 48; (2024) 281 CLR 484 at 502[37].

[73] [2023] NSWCA 72 at [131].

[74] With whom Bell CJ and Leeming JA agreed.

[75] [1977] AC 890 at 903.

[76] Tradax Export SA v Dorada Compania Navierasa (The "Lutetia") [1982] 2 Lloyd's REP 140 at 157.

[77] [2019] VSCA 167 at [114], [119].

[78] [1997] EWCA Civ 1.

[79] Middleton v Aon Risk Services Australia Ltd [2008] WASCA 239 at [22]- [23] and [80].

[80] Eslea Holdings Ltd v Butts (1986) 6 NSWLR 175 at 188.

[81] Bell Group Ltd (in liq) v Westpac [2008] WASC 239; (2009) 39 WAR 1 at 461-462 [3466]-[3469].

[82] Ecosse Property Holdings Pty Ltd v Gee Dee Nominees Pty Ltd [2017] HCA 12; (2017) 261 CLR 544 at 551.

[84] Amcor Limited v Peter James Ramsay [2018] VSC 75 at [159].

[85] Tri-Star's Primary Outline [86].

[86] Low v Bouverie [1891] 3 Ch 82 at [106].

[89] Butcher v Lachlan Elder Realty Pty Limited [2004] HCA 60; (2004) 218 CLR 592 at 604 [37]; Miller & Associates Insurance Broking Pty Ltd v BMW Australia Finance Limited [2010] HCA 31; (2010) 241 CLR 357 at 384 [91].

[90] [2006] VSC 507 at [741].

[91] Tri-Star's primary outline [132].

[92] Bluehaven Enterprises Ltd v Tully [2006] 4 LRC 658 at [22].

[93] (1866) LR 1 HL 129.

[94] (1880) 15 Ch D 96.

[95] [1971] AC 850 at 884.

[96] 15 Ch D 96.

[97] [1982] QB 133 at 146-147.

[102] [2018] NSWSC 442 at [920].

[105] [2006] 4 LRC 658 at 669 [27].

[107] [2024] QCA 218 at [13] and [14].

[108] With whom Callaghan and Crowley JJ agreed.

[110] APLNG's outline [158] and [159].

[112] Q v E [2020] NSWCA 220; (2020) 383 ALR 469 at 499 [123].

[115] [1933] HCA 61; (1933) 49 CLR 507 at 547.

[116] Sidhu v Van Dyke (2014) 251 CLR 505 at 523 [59].

[117] [2024] HCA 48; (2024) 281 CLR 484 at [39]- [41].

[118] Gageler CJ, Gordon, Edelman and Beech-Jones JJ.

[119] [1937] HCA 58; (1937) 59 CLR 641 at 674.

[120] Ibid at 674-675; AFSL v Hills Industries (2014) 253 CLR 560 at [86].

[121] Q v E [2020] NSWCA 220; (2020) 383 ALR 469 at 505 [154].

[122] AFSL v Hills Industries (2014) 253 CLR 560 at 600.

[123] Newbon v City Mutual Life Assurance Society Ltd [1935] HCA 33; (1935) 52 CLR 723 at 735_._

[125] (2014) 251 CLR 505 at 526.

[126] French CJ, Kiefel, Bell and Keane JJ.

[127] Amalgamated Investment & Property Company Ltd (In Liq) v Texas Commerce International Bank Ltd [1982] QB 84 at 104-105; Sidhu v Van Dyke (2014) 251 CLR 505.

[128] Sidhu v Van Dyke (2014) 251 CLR 505 at 531-532 [91]-[94].

[129] Q v E [2020] NSWCA 220; (2020) 383 ALR 469 at 506 [156].

[133] [2010] NSWCA 84; (2010) 78 NSWLR 483 at [5].

[134] (2014) 253 CLR 560 at [88].

[136] (2014) 253 CLR 560 to 622-623 [150].

[137] [2020] NSWCA 220; (2020) 383 ALR 469 at 500 [127].

[139] [2018] NSWSC 442 at [940].

[140] I & L Securities v HTW Valuers (Brisbane) Pty Ltd [2002] HCA 41; (2002) 210 CLR 109 at [57].

[141] Sellars v Adelaide Petroleum NL [1994] HCA 4; (1994) 179 CLR 332 at 348.

[143] Haven Pty Ltd v Webster [2005] NSWCA 182 at [116(c)].

[145] Campbell v Backoffice Investments Pty Ltd (2009) 238 CLR 304 at [143].

[146] [1994] HCA 4; (1994) 179 CLR 332 at 348.

[147] Mason CJ, Dawson, Toohey and Gaudron JJ.

[148] Sellars v Adelaide Petroleum NL [1994] HCA 4; (1994) 179 CLR 332 at 348.

[155] Tri-Star's primary outline [180].

[156] Tri-Star's primary outline [180].

[159] As to the misleading and deceptive conduct claims, see the pleading at [247(a)].

[161] The pleading paragraph 235[ea] and [f].

[162] Tri-Star's Primary Outline [191(d)].

[168] [2010] NSWCA 84; 78 NSWLR 483 at 486.

[171] The pleading [235](a), (aa), (ab), (b), (bb).

[173] The pleading [250A] particulars (i).

[175] Prudential Assurance Co Ltd v Newman Industries Ltd (No 2) [1982] Ch 204 at 222-3.

[176] Garner v Central Innovation Pty Ltd [2022] FCAFC 64 at [106].

[177] Digi-Tech (Aust) Ltd v Brand [2004] NSWCA 58 and Australian Breeders Co-Operative Society Ltd v Jones [1997] FCA 1405; (1997) 150 ALR 488.

[178] Priestley v Priestley [2016] NSWSC 1096 at [162]- [172]; Priestley v Priestley [2017] NSWCA 155 at [169]; Densom v Cootamundra Racecourse Trust [2000] NSWSC 1072 at [73]- [75]

[179] David Securities Pty Ltd v Commonwealth Bank of Australia [1992] HCA 48; (1992) 175 CLR 353 at 376-77, 395-396 and 402.

[180] Salib v Gakas [2010] NSWSC 505 at [328].

[181] [2016] NSWSC 1096 at [176].

[182] Streeter v Western Areas Exploration Pty Ltd (No. 2) [2011] WASCA 17; (2011) 278 ALR 291 at 632.

[183] See by way example the pleading at [134](b)(v), (vi), (viii), (ix), (x).

[184] Sloan v Arnold Thomas & Becker Pty Ltd [2019] VSC 292 at [17]- [18] and [28].