Cadbury Schweppes Pty Limited v Darrell Lea Chocolate Shops Pty Limited

ON APPEAL FROM A SINGLE JUDGE OF THE FEDERAL COURT OF AUSTRALIA

Background and Short Synopsis of Contentions 14 By its notice of appeal, the appellant Cadbury Schweppes Pty Ltd ("Cadbury") contends that orders of the primary judge (Heerey J) dismissing its action against Darrell Lea Chocolate Shops Pty Ltd ("Darrell Lea") (Cadbury Schweppes v Darrell Lea (No. 8) [2008] FCA 470; (2008) 75 IPR 557; (2008) ATPR 42‑229) for relief in respect of contended misleading and deceptive conduct and passing off arising out of Darrell Lea's adoption of a colour purple similar to Cadbury purple in connection with its business and chocolate products, should be set aside and a new trial ordered because in the circumstances of the case, a fair‑minded lay observer might reasonably apprehend that the primary judge mightnot bring an impartial and unbiased mind to the resolution of the questions he was required to decide at trial. 15 That apprehension of bias is said to arise as the primary judge had previously formed a view about the admissibility and more importantly the utility of particular expert evidence sought to be adduced from three experts on behalf of Cadbury. That evidence was wrongly excluded at an initial trial resulting in an appeal and an order of the Full Court for a further hearing before the primary judge (rather than a re‑trial) at which Cadbury would have another opportunity of adducing the disputed evidence as though the case were part heard subject to any proper objections to the disputed evidence and rulings on those objections (Cadbury Schweppes v Darrell Lea [2007] FCAFC 70; (2007) 159 FCR 397; (2007) 239 ALR 662; (2007) 72 IPR 261 per Black CJ, Emmett and Middleton JJ (the "initial reasons"), amplified by the Full Court's further reasons in Cadbury Schweppes v Darrell Lea (No. 2) [2007] FCAFC 102; (2007) 29 ATPR 42‑175 (the "further reasons")). Cadbury says that since the primary judge in deciding to exclude the expert evidence at the first hearing expressed views a lay person would regard as critical of or very sceptical of the value of the expert evidence (the content of which will be examined in these reasons) and, in particular, the evidence of Dr Gibbs, the primary judge, upon Cadbury's motion for disqualification, ought to have disqualified himself from the conduct of the further hearing. Cadbury says the primary judge could, by then, no longer bring by reason of pre‑judgment, an impartial mind to the assessment of the expert evidence. Cadbury says that applying the recognised test a lay observer might take the view that the primary judge might not bring an open mind to the analysis of that evidence (a test the profession describes as the "double might" test of apprehended bias). 16 Secondly, Cadbury says that the primary judge expressed strong views reflective of the primary judge's conviction as to the lack of merit in Cadbury's case. Thus, it is said, a fair‑minded lay observer might take the view that the primary judge might not bring an independent and open mind to the determination of important factual questions at the further hearing. Cadbury says that because it was wrongly deprived of its expert evidence, it was not able to directly put that expert opinion evidence concerning the cognitive responses to colour in impulse purchasing by consumers, to a witness for Darrell Lea, Ms McGlinchey, accepted as truthful by the primary judge, on the critical question of whether Darrell Lea consciously appropriated Cadbury's reputation by use of a similar shade of purple in its business and for its chocolate products. That question of appropriation was to be determined by the primary judge on the further hearing having regard to independent judgments to be made as to the admissibility of the expert evidence and factual findings as to intention in the use by Darrell Lea of a similar colour purple to Cadbury purple. 17 Thirdly, Cadbury says that although the Full Court in its initial and further reasons elected to remit the proceeding to the primary judge to conduct the further hearing, determine objections to the expert evidence and in doing so consider the exercise of the discretion arising under s 135 of the Evidence Act 1995 (Cth) as a matter "entirely for the primary judge", the Full Court did not itself determine that in the circumstances no question of apprehended bias arose notwithstanding the observations in the initial reasons particularly at [113] and [114], in these terms: 113. There is no reason to conclude that his Honour would not bring a fair and open mind to the question of specific objections to the disputed evidence and the resolution of the issues in the light of any part of the disputed evidence that might ultimately be admitted, consistently with these reasons, and 114. In these circumstances, there is no reason why the proceeding should not be remitted to the primary judge for further hearing. Of course, if the primary judge were prepared to entertain a submission that he would not be able to bring an open mind to the resolution of the proceeding in the light of his Honour's earlier rulings both on the disputed evidence and in the final decision, it would be a matter for his Honour to decide whether he considered it was appropriate for the proceeding to be referred to another judge for a retrial ab initio. 18 Thus, the election by the Full Court to remit the matter to the primary judge (coupled with the second sentence of [114]) ought not to be viewed, it is said, as a finding or determination that the primary judge might embark upon a further hearing free, so far as the Full Court was concerned, of any reasonable apprehension in the mind of a fair‑minded lay observer that the primary judge might not bring an impartial and unbiased mind to the resolution of the questions before him. 19 That follows it is said because although Cadbury sought before the Full Court an order for a re‑hearing before another Judge and in doing so counsel for Cadbury briefly articulated a concern as to "appearance of bias" should the primary judge conduct a re‑hearing, the question was not argued, the reference was brief, the matter was expressly left to the primary judge to determine whether he felt he could or could not conduct the further hearing according to law in all the circumstances, and to now construe the quoted references as a finding dispositive of a contention of apprehended bias represents procedural unfairness. 20 Cadbury says it wants to be clear that no contention is made of actual bias on the part of the primary judge. 21 Darrell Lea says a number of things in response. 22 First, rulings by the primary judge going to the expert evidence and particularly that of Dr Gibbs were directed to questions of admissibility not findings reflecting concluded views as to the credit of the experts or views as to the facts or inferences to be drawn from the evidence. In other words, the primary judge has not analysed and weighed the expert evidence for the purpose of making substantive findings about it. 23 Secondly, the primary judge made an error of law in excluding the expert evidence. The error was corrected by appellate review, acknowledged by the primary judge and the subject of an expression of regret on the part of the primary judge. Thus, the lay observer acting reasonably would see without legal nuance or deconstructed subtlety, a plainly corrected error as to admissibility resulting in a remittal to the primary judge to consider again the admissibility of the contested evidence. Such a lay observer would also see that grounds of objection to the disputed evidence would be considered and the evidence, if admitted after proper analysis of those grounds, would be considered consistent with the professional standards of a judge applying the law and acting according to law consistent with the correction by the Full Court. 24 Thirdly, the decision of the Full Court to remit the matter to the primary judge in the context of a request by Cadbury for remittal to another judge, made against the background of the remarks of the Full Court at [113] and [114] of the initial reasons, must necessarily convey to the lay observer acting reasonably that the primary judge would embark upon the further hearing corrected as to the error he had made and then give rational consideration to all the evidence admitted before him according to law. Fourthly, apart from a contention concerning Ms McGlinchey, Cadbury accepts that the findings of fact stand as rational unchallenged findings based upon a careful consideration of the evidence and thus the lay observer would see that no question of apprehended bias would arise should the primary judge exclude the evidence for the purposes of the further hearing having regard to the discretion to be exercised under s 135 of the Evidence Act or upon any other ground properly made out. 25 Fifthly, the lay observer in acting reasonably would have regard to and be informed by the primary judge's essential reasons for excluding the expert evidence; the emphasis in the particular language adopted by the primary judge; both the initial and further reasons of the Full Court for its orders and directions in the matter; the primary judge's reasons for refusing to disqualify himself; and the procedural directions made by the primary judge for the further hearing of the matter. Ultimately, the question of whether a fair‑minded lay observer might reasonably apprehend that the primary judge might not bring an impartial and unbiased mind to the resolution of particular questions is to be determined having regard to the constructive state of knowledge to be imputed to the lay observer. In other words, context, as in so many other areas of human conduct, is all important. 26 Sixthly, the primary judge made a number of important procedural orders to frame a fair further hearing including granting leave to Cadbury to amend its statement of claim; an order that Darrell Lea provide Cadbury with a statement of its objections to the expert affidavits; an order granting Cadbury leave to supplement its material and address Darrell Lea's objections; and an order granting Darrell Lea leave to file material in response. Accordingly, the lay observer would see, it is said, the expression of fairness and independent method in enabling the expert evidence to come forward with every opportunity afforded to Cadbury to deal with articulated objections and, if necessary, supplement its material. Further, the case to be made at the further hearing changed by reason of amendments to the statement of claim from one of exclusive reputation in Cadbury in the colour Cadbury purple to one of substantial repute in the colour Cadbury purple. Darrell Lea says the lay observer would note that a different case had thus emerged for determination at the further hearing. 27 As to Ms McGlinchey, Darrell Lea says her evidence went to her decision‑making process in electing to use a colour purple in connection with Darrell Lea's business and chocolate confectionary in the relevant period, and expert evidence concerning cognitive or behavioural responses to a colour in impulse purchases by consumers could not, it is said, go to the issue of Ms McGlinchey's purpose or intention. In any event, Cadbury's counsel, Mr Myers QC, vigorously put the case to Ms McGlinchey at trial that she had adopted a similar colour purple to Cadbury purple so as to associate Darrell Lea's brands with the good name of Cadbury. Ms McGlinchey denied those propositions. Thus, Cadbury was not constrained or inhibited, it is said, in the case it put to Ms McGlinchey on that central question.

The present appeal 28 By its notice of appeal, Cadbury relies upon 17 grounds of appeal. On 5 August 2008, the Chief Justice, no doubt mindful of the observations of Kirby and Crennan JJ at [117] in Concrete Pty Ltd v Parramatta Design & Developments Pty Ltd (2007) 229 CLR 577 (with whom Gummow ACJ expressed agreement ([2]‑[3])) and observations of Callinan J at [172] - [173] in Concrete), made orders that the grounds of appeal going to contentions of apprehended bias (grounds 1 and 2 of the notice of appeal) were to be listed for determination prior to the hearing of the appeal in relation to the remaining grounds 3 to 17. Accordingly, the present appeal is confined to the issues of apprehended bias.

The sequence of decisions 29 In order to deal with the various contentions, it is necessary to set out the sequence of decisions and the essential reasoning. 30 Cadbury having commenced and discontinued proceedings in 2003 commenced further proceedings in 2005 (VID555 of 2005). The trial of that proceeding commenced before Heerey J on 20 March 2006. In that action, Cadbury contended that "Cadbury" is regarded by members of the public as synonymous with chocolate confectionary; since 1985 Cadbury has widely marketed itself and its Cadbury chocolate confectionary products by reference to the colour "Cadbury purple"; the colour Cadbury purple is perceived by consumers in eight "pantone" shades of purple identified by particular pantone colour code numbers; Cadbury so marketed itself and its products as to lead consumers to associate Cadbury purple with Cadbury and its confectionary; by 1995, Cadbury had established a valuable exclusive reputation and goodwill in Cadbury purple; since late 2001, Darrell Lea used in the conduct of its chocolate confectionary business a colour purple bearing a striking and obvious likeness to Cadbury purple and thus wrongfully appropriated and converted to its own use Cadbury's reputation in Cadbury purple; through the use by Darrell Lea of such a colour, Darrell Lea made a series of representations in trade or commerce such as, a representation that use of a similar colour to Cadbury purple occurred under licence from Cadbury or alternatively, Darrell Lea enjoyed a relevant connection with, approval of or sponsorship by, Cadbury. Thus, Cadbury alleged contraventions of ss 52, 53(c) and 53(d) of the Trade Practices Act 1974 (Cth) and passing off. 31 At the trial of the action, Cadbury sought to read and rely upon two affidavits of Dr Brian John Gibbs, an Associate Professor of Marketing and Behavioural Science in the Melbourne Business School at the University of Melbourne. Cadbury also sought to rely upon affidavits from two further experts, Mr Constantino Stavros, a Senior Lecturer in the School of Economics, Finance and Marketing at RMIT University, Melbourne, and Mr Timothy Raymond Riches, the Managing Director of a large marketing services group called FutureBrand. Objection was taken to the tender of the affidavits of Dr Brian Gibbs. The determination of those objections also determined the admissibility of the affidavits of Mr Stavros and Mr Riches. Objection was taken on the ground that the elements of s 79 of the Evidence Act as an exception to the prohibition in s 76 of the Evidence Act on the reception of opinion evidence were not made out. Section 79 contemplates specialised knowledge in the witness based on his or her training, study and experience and the formulation of an opinion that is wholly or substantially based on that knowledge. Alternatively, Darrell Lea contended that the affidavits of Dr Gibbs ought to be excluded in the exercise of the primary judge's discretion under s 135 of the Evidence Act as the probative value of the affidavits was said to be substantially outweighed by the time that would be wasted in dealing with and responding to the affidavits.

The evidence ruling 32 The primary judge accepted that Dr Gibbs has specialised knowledge (Cadbury Schweppes v Darrell Lea [2006] FCA 363; (2006) 228 ALR 719; 28 ATPR 42‑112 (the "evidence ruling")). He holds a Doctorate in Behavioural Science and Marketing from the Graduate School of Business at the University of Chicago and has other significant experience within international universities of real standing. The two affidavits of Dr Gibbs comprised 90 pages including exhibits. The evidence was directed to these matters. The colour Cadbury purple is strongly associated with the Cadbury brand. Purple is an activator of Cadbury's brand equity triggering tangible and intangible brand judgments in the mind of consumers. Darrell Lea's use of purple is likely to cause four information processing errors to occur among consumers of chocolate confectionary. The four errors are described as misidentification, miscuing, misinference and misassociation. Dr Gibbs described those four errors, relevantly, in these terms: Misidentification is when consumers seeking to buy Cadbury chocolate mistakenly identify a Darrell Lea product as a Cadbury product and therefore buy the Darrell Lea product by mistake. Harm [is caused to Cadbury] due to blame from consumers for the confusing common use of colour and damaged consumer attitudes due to cognitive dissonance [a state of discomfort produced by inconsistencies between simultaneously held beliefs or between beliefs and behaviour] or due to violated expectations. Miscuing is when consumers use purple as a spurious cue in decision‑making and choice; in this capacity the colour can function as a decision‑heuristic [a shorthand rule or "rule of thumb" functioning to reduce decision‑making effort while maintaining an acceptable level of accuracy] cue … Misinference is when consumers in trying to make sense of the common use of purple by Darrell Lea and Cadbury draw mistaken inferences about one or both of the brands. Misassociation is when consumers mistakenly link Cadbury brand association with Darrell Lea and vice versa as a result of the two brands associative networks [a framework for understanding how pieces of semantic information interact in an individual's memory in which concepts or other information stored in memory are represented by nodes that are inter‑connected in a network of links] having become connected in consumers' minds through the common use of purple. [emphasis contained within the original quoted paragraphs] 33 Dr Gibbs considered that Darrell Lea's use of purple gave rise to judgment errors made by consumers, retailers, investors and Cadbury employees causing particular identified errors and a reduction in what he described as the "perceptual distinctiveness" of Cadbury products and thus a loss of sales. 34 The primary judge dealt with the objections in this way. Although the "prime ground" on which Darrell Lea objected to admissibility was that Dr Gibbs's opinions were based on market research reports not proved in evidence and not likely to be proved, the lack of proof of a substantial part of the factual basis for Dr Gibbs's opinions did not render his evidence inadmissible under s 79 of the Evidence Act ([6] and [7] of the evidence ruling). His Honour concluded that such lack of proof merely goes to weight. Nevertheless, the evidence was found to be inadmissible because s 79 of the Evidence Act,like the common law, requires the opinion to address an area of knowledge outside the experience of ordinary persons. Since the making of consumer decisions for the purchase of everyday items of commerce such as low cost chocolate confectionary did not fall outside the knowledge or experience of ordinary persons, Dr Gibbs's evidence was found to be inadmissible ([12] of the evidence ruling). The primary judge then identified "another route" leading to the same result, that is, a proposition that ordinary human behaviour is not a matter probative in courts by opinion evidence at all whether expert or otherwise. Speaking of the evidence in this case, his Honour said this: 16. But with respect, the whole raison d'etre of Dr Gibbs' evidence is to attempt to persuade the court what ordinary human nature will lead people to do when making purchasing decisions about Darrell Lea chocolates, given the respective packaging, advertising etc of that firm and Cadbury. As the very nature of Dr Gibbs' discipline conveys, he is concerned with the science of human behaviour. That is without doubt an area of specialised knowledge. But Transport Publishing Co Pty Ltd v The Literature Board of Review (1956) 99 CLR 111 says that ordinary human behaviour is not a matter to be proved in courts by opinion evidence, whether expert or otherwise. [emphasis added] 35 His Honour relied upon Cat Media Pty Ltd v Opti‑Healthcare Pty Ltd [2003] ASAL 55-103; [2003] FCA 133 at [55], Domain Names Australia Pty Ltd v .au Domain Administration Ltd (2004) 139 FCR 215 at [21] and an observation of the learned author in J D Heydon's Cross on Evidence (7th Australian Ed, 2004) to support the view that expert opinion evidence concerning the responses of a wide segment of the general public or a group which does not command specialised recognition, attracted no more than nominal weight. Applying those authorities to the facts, his Honour made this observation: 32. The present case is concerned with the brand names, colours and get‑up of rival manufacturers of chocolate, and the likely effect of those features on retail purchasing decisions by consumers. Chocolate is an inexpensive, every day product sold in hundreds of thousands of retail outlets throughout this country. Virtually the whole of the Australian population over the age of about eight years are purchasers or potential purchasers. In no way can consumers of chocolate be considered as a "special category of persons" within the meaning of the Transport Publishing rule. The questions thrown up by this case are quintessentially questions of fact within the experience and knowledge of a trier of fact. [emphasis added] 36 In response to Cadbury's submissions pressing the utility of Dr Gibbs's evidence, his Honour said this: 23. Senior counsel for Cadbury referred to the assistance he said I could receive from Dr Gibbs' evidence and how it could be helpful. Without wishing to seem ungrateful, or disrespectful to Dr Gibbs, I think the evidence would not be helpful at all. Rather, it would create many areas of disputation with opposing experts and greatly complicate and lengthen the trial of this proceeding. The observations of Branson J in Cat Media are very much in point. [emphasis added] 37 Those observations of Branson J referred to at [23] were that expert evidence going to the appeal of a product to a wide segment of the general public was of no real assistance and that where a claim is essentially a matter for the Court's impression, expert views which are merely impressionistic can be given no more than nominal weight. Of course, the reference to weight itself suggests relevance and therefore admissibility in any event subject to s 135. The primary judge ruled the affidavits of Dr Gibbs inadmissible and determined that were they admissible, he would exercise the discretion under s 135 of the Evidence Act to refuse to admit them. The considerations which would have led the primary judge to exercise the discretion in that way had the question arisen, included these: 25. Much of the factual material relied on by Dr Gibbs is not in evidence, or likely to be in evidence, or is vague, tendentious and of little weight. As acknowledged above, such matters go to weight rather than admissibility, but by the same token are relevant in considering probative value for the purposes of s 135. [emphasis added] 26. Cadbury have already called a number of witnesses who gave unexceptionable evidence about Cadbury's marketing, advertising, product presentation and the like. However, Dr Gibbs does not rely on such evidence but rather on a number of market research reports by persons who will not be called as witnesses. Some of these persons swore affidavits which Cadbury sought leave to file well past the time fixed by trial directions. I refused leave on procedural fairness grounds. In respect of others, who were not going to be called in any event, I ruled that their reports were not business records within s 69. 38 The primary judge referred to a document briefed to Dr Gibbs by Cadbury's solicitors which was described as an "Overview of the History of Cadbury and the Colour 'Purple'" ("the Overview"). His Honour made these observations: 27. It [the Overview] includes vague and self‑serving statements such as: "Cadbury's mission statement is simply 'Cadbury means quality', this is Cadbury's promise and this is what the company considers its reputation is built on. The well established corporate colours of purple and gold and the Cadbury script logo, which are so prominent on livery, signs, stationery, printed material and the brands themselves are a visual statement of the company's authority within the market. Cadbury considers these elements lend themselves to Cadbury's being 'the First Name in Chocolate'." 28. Dr Gibbs states that he has assumed that the purple colour used by Darrell Lea is "similar to that used by Cadbury". This seems to assume one of the critical issues in the case. What is "similar" in this context? Darrell Lea says that its colour is lighter, more of a lilac or boysenberry, than the dark purple used by Cadbury. Moreover, Darrell Lea says that overtime there have been variations in the shade of purple used by Cadbury. At a late stage Dr Gibbs does deal briefly with a question imposed in his instructions, namely whether "the shade of purple used by Darrell Lea (must) bear a striking and obvious likeness to Cadbury Purple". He has had "difficulty in answering this question definitively, as to do so would ultimately hinge upon a psychophysical quantification of what counts as 'striking and obvious', and which may in any case require field data in order to be answered properly". Nevertheless, he ventures the opinion that a consumer "may perceive a fairly wide range of purples to be Cadbury purple". He states that research from a "sensation/perception psychologist's website" the address of which is given, shows that whilst about 150 hues can be discriminated across the colour spectrum in side‑by‑side comparison, only about 17 are discernible in colour memory". His evidence on this point seems to amount to part speculation and part unnecessary intellectualisation of a simple question of consumer product comparison. The potential for time‑wasting cross‑examination is obvious. [emphasis added] 39 As to policy matters influencing the exercise of the discretion, his Honour said this: 30. There is a particular public interest in having litigation of this kind resolved fairly and efficiently. It is harmful for consumers and traders and society as a whole if consumers are led into making choices based on false or misleading information by trade rivals. On the other hand, it is also harmful for society if traders are inhibited from using competitive trading methods which are in truth lawful even though alleged by trade rivals to be misleading. 31. The law on s 52 and passing off is well settled. Factual issues which arise in the context of widely marketed consumer goods and services are often straightforward. The present case is a good example. If it becomes accepted that the only way to conduct these cases is by the calling of evidence like that of Dr Gibbs, solicitors will feel they have to advise such a course for fear of being sued for negligence if they do not. Large companies will be in a position to hold out the threat of ruinous costs over smaller competitors ("emboldened competitors" as Dr Gibbs would have it). Competition will be stifled. The delicate balance between the laws of fair trading and the laws of competition will be distorted. 40 The task undertaken by the primary judge in looking at the expert evidence was conditioned by its contended admissibility and its relationship with the elements of s 79 of the Evidence Act, in particular. The task was not one of determining facts in controversy through the critical evaluation and application of admissible expert opinion evidence to the dispositive resolution of issues in controversy. Nor did the task involve the assessment of the experts personally in terms of their cooperation and contribution as experts in aiding the Court in resolving facts and issues in controversy, that is, the broader credit or reliability of each expert. For example, the task did not involve the kind of evaluation undertaken by Goldberg J in Qantas Airways Limited [2004] ACompT9, where his Honour made this evaluation: 216. Obviously, parties will call upon experts whose opinions support their view of the case. However, it is not appropriate for an expert witness to act as an advocate for the instructing party, at all costs and professional witnesses should be willing to concede points which whilst not advancing the case of the party engaging them, they believe to be open as a fair and reasonable assessment on the material before them. … 221. Generally, whether an expert's opinion is confined to his or her area of expertise and whether experts state the factual basis upon which they have formed their opinion, are useful considerations in determining at what point an expert witness ceases to be impartial and has moved beyond the bounds of legitimacy into advocating for a party. Another indicator is the willingness of an expert to respond to questions whose answers may provide support for a view which is contrary to the interests of the party calling them. 222. With regard to the latter, we note that on many occasions in the present proceeding two experts in particular, being Mr Ergas, called on behalf of the applicants, and Professor Timothy Hazledine, a Professor of Economics at the University of Auckland … appeared reluctant to respond to questions whose answers, might have been adverse to the case put by the party calling them. Instead, they provided non‑responsive answers and deviated to discussions of other issues which supported the case of [others]. 41 Rather, the primary judge applied an analytical framework to the admissibility arguments which involved an examination of the scope and focus of the affidavits of Dr Gibbs and the issues in controversy to which that evidence was said to be relevant and probative; and some at least of the reports and material upon which the expression of opinion rested or was said to rest. By that analytical framework, the primary judge dealt with prime objection of lack of proof of foundation facts supporting the opinion and the relevant authorities; and secondly, a notion of inadmissibility due to opinions on matters not outside the knowledge or experience of ordinary persons, and authorities his Honour thought supported that notion. Thirdly, at [23] of the evidence ruling, in further reliance on Cat Media the primary judge applied the notion that Dr Gibbs's evidence went to matters not outside ordinary human experience in rejecting the utility or "helpfulness at all" of the evidence. Rather than being helpful, the primary judge thought its reception into evidence would create areas of disputation, draw in opposing experts and complicate and lengthen the trial. Cadbury says the primary judge's expression of opinion that the evidence would not be helpful at all is emblematic of a formed view of the evidence the lay observer might reasonably think the primary judge might find difficult to alter, upon reconsideration at a further hearing. 42 Each of these conclusions however derives from the application of a structured process of reasoning about the evidence and its admissibility on one ground or another. The conclusion that Dr Gibbs's evidence would not be helpful at all is itself based on the application of one such ground rather than a substantive determination of the evidence in resolving questions of fact in controversy. Since the analysis on admissibility failed to take account of s 80 of the Evidence Act, the analysis reflected an error of law which required the question of admissibility to be considered afresh in the light of the correct analytical framework applying s 80 of the Evidence Act and taking account of objections to admissibility and the exercise of discretion under s 135 of the Evidence Act. The central matter was the process of reasoning on admissibility not conclusions about the experts or facts found in reliance on a substantive evaluation of the expert evidence in its application to issues in controversy. 43 The primary judge was however more directly critical of the expert evidence when explaining why (if it had become relevant) the discretion might have been exercised against admission of the evidence. The criticism at [25] went to the quality of the foundation facts supporting the opinion evidence as "vague, tendentious and of little weight". 44 The criticism at [28] went to the method adopted by Dr Gibbs in assuming for the purposes of his opinion, a use by Darrell Lea of a colour purple similar to Cadbury purple and the difficulty Dr Gibbs expressed in answering the question put to him in his instructions of whether the shade of purple used by Darrell Lea must bear a striking and obvious likeness to Cadbury purple before one or more of the four information processing errors might be evident. The primary judge noted that Dr Gibbs believed a definitive answer required a "psychophysical quantification" of what is "striking and obvious" and field data to be gathered, yet Dr Gibbs was willing to venture an opinion that consumers might see a fairly wide range of purple to be Cadbury purple. The primary judge noted the support quoted by Dr Gibbs of a particular website suggesting 17 hues across the colour spectrum can be discerned in "colour memory". 45 It is fair to say that the primary judge in making these observations was drawing attention to apparent methodological anomalies in the reasoning of Dr Gibbs thus leading to the conclusion that the evidence on colour comparison seemed to "amount to part speculation and part unnecessary intellectualisation of a simple question of consumer product comparison". That led his Honour to the ultimate conclusion that the potential for "time wasting cross‑examination was obvious". Thus, the discretion ought to be exercised against admitting the material. 46 To the extent that Dr Gibbs thought a proper answer to the particular question required structured quantification and possibly field data, the suggestion that the proffered opinion was part speculation might well be seen as unexceptional. To the extent that the proffered opinion on consumer product colour comparison is criticised as part "unnecessary intellectualisation", the primary judge seems to be reflecting a conclusion based fundamentally on his Honour's earlier assessment that what is being offered by Dr Gibbs is an opinion about retail purchasing decisions concerning inexpensive every day confectionary products sold throughout the country and bought by consumers from, generally, eight years of age [32]. That of course as the Full Court pointed out at [54] and [55] and concluded at [57] of the initial reasons, did not render the opinion inadmissible. At [57], the Court in its initial reasons said: 57. The primary judge concluded, however, that it is a condition of the admissibility of opinion evidence that the opinion relates to an issue that is outside the knowledge or experience of ordinary persons. In so far as that was the reason for concluding that the opinions of Dr Gibbs were inadmissible, his Honour erred. The fact that an opinion is expressed concerning the making of consumer decisions for the purchase of every day items of commerce does not disqualify the opinion from being admissible, so long as s 79 is satisfied.

Judgment consequent upon the first hearing 47 The primary judge dismissed Cadbury's action (Cadbury Schweppes v Darrell Lea (No. 4) [2006] FCA 446; (2006) 229 ALR 136; (2006) 69 IPR 23). Of particular importance in the case was the use made by Darrell Lea of darker shades of purple in the packaging of its seasonal products at Christmas in the years 2000 to 2004. His Honour found that that shade of purple was "like that used by Cadbury" and observed that if Darrell Lea's decision to adopt it had been made with the intention of misleading consumers as to an association with Cadbury, that would be strong evidence that misleading conduct in fact occurred. As to that, Ms McGlinchey gave evidence for Darrell Lea of research into colour themes and identified particular commercial reasons for adopting the particular shade of purple. She admitted in cross‑examination that when adopting the shade of purple for Darrell Lea's use, she knew Cadbury sold its confectionary predominantly in a purple colour. At [48], the primary judge noted that Ms McGlinchey strongly denied that she, having adopted the colour, was using purple to associate Darrell Lea brands with the good name of Cadbury or that she had used purple to copy Cadbury. The primary judge accepted Ms McGlinchey as a witness of truth. The primary judge noted [82] Cadbury's contention that the colour purple had developed a secondary meaning as an identifier of Cadbury chocolate products and that such a question is purely one of fact [83]. His Honour concluded that whilst purple may prompt in the reasonable consumer's mind a remembrance that purple has been associated with Cadbury chocolate, it would not lead such a consumer to the conclusion that a purple packaged product must be a Cadbury product. His Honour considered the Cadbury "brand architecture" (the name Cadbury; colour purple; and the glass and a half device) and found the colour purple is always associated by Cadbury in point of sale material with the name Cadbury. As to the "likely behaviour of shoppers or consumers in relation to goods normally sold to the general public", his Honour again noted that "this is a 'jury question' that is a question … for the Tribunal of fact" and as to that his Honour concluded at [94] that colour plays an important part in product recognition by consumers but recognition is triggered, in this case, by brand, logos and particularly the place from which the product is presented for sale. As to place of sale, the primary judge noted that the bulk of Darrell Lea sales (70%) occurred through their own shops with 30% of sales occurring in sites such as newsagencies and pharmacies where stock is placed in "freestanding units" for sale. The primary judge made the following findings among others: 96. There is wide awareness amongst Australian consumers of the use by Cadbury of a dark purple colour (i) in connection with the marketing, packaging and presentation of certain chocolate products particularly Cadbury Dairy Milk and other block milk chocolate products, and (ii) as a corporate colour. 100. Cadbury's use of purple in marketing advertising and promotion is, as is seen by consumers to be, inextricably bound up with the well known name Cadbury in its distinctive script. Cadbury never uses the colour purple in isolation as an indication of trade. 103. Darrell Lea is a name well known in connection with chocolate in those parts of Australia where it operates, even though not as well known as Cadbury. 104. The names Darrell Lea and Cadbury are quite distinct in sound and appearance (especially with the respective scripts the parties have adopted) and not likely to be mistaken for each other. 105. Darrell Lea has since at least Christmas 2000 used in its marketing, packaging, promotion and point of sale presentation a purple colour much like that used by Cadbury [emphasis added]. There has been particular use at Christmas 2000 to 2004 inclusive and also uses at other times. Such usage has diminished and purple has been to a significant extent replaced by blue since 2004. 106. Darrell Lea did not adopt the colour purple with the intention of leading consumers to believe its products were Cadbury products or that it, or its products, had some kind of association with Cadbury. 111. Colour recognition or attraction can play an important part in consumer decisions to purchase chocolate. 112. Consumer decisions to purchase chocolate are often made quickly and on impulse but not necessarily irrationally. Price and brand recognition can play an important part.

The Full Court's initial reasons 48 The Full Court at [57] identified the primary judge's error of law in excluding the expert evidence. As to the considerations influencing the exercise of discretion under s 135 of the Evidence Act had the expert evidence been treated as admissible, the Full Court noted that Dr Gibbs's assumption was not misplaced as the ultimate finding of fact was use by Darrell Lea of a similar colour purple and as to the burden of wasted time by not excluding the evidence, the Court considered that the primary judge could have contained unnecessary cross‑examination if similarity of colour had not seriously been in issue. At [75], the Court said: 75. The opinions of Dr Gibbs in the section of his principal affidavit that dealt with Basic Principles and Background Issues, contained material that, if accepted, could have a significant bearing on a judge's understanding of consumer behaviour. Perhaps more significant would be his opinions on consumer information‑processing errors. That evidence had some probative value within the meaning of s 135 of the Evidence Act. 49 At [85], the Court found that the evidence of Dr Gibbs might have influenced the findings of the primary judge at [96], [100], [103], [104], [105], [111] and [112] of his Honour's reasons. Most of those findings were in any event favourable to Cadbury. Whilst Cadbury contended for error by the primary judge in failing to find that the overall impression of Darrell Lea's packaging in the relevant period was capable of conveying a representation of association with Cadbury to a significant body of reasonable consumers, Cadbury acknowledged that the primary judge had regard to all the relevant evidence before him and reached his conclusion on a rational basis. Assuming the disputed evidence had been properly rejected, no error thus arose. However, since all that Cadbury accepted was that the "truncated evidence" [95] left open the findings made by the primary judge, the Court found "a different conclusion might be reached at another hearing with additional admissible evidence, even before the primary judge" [95] (emphasis added). At [100], the Court said: 100. The Court could not conclude, simply by reason of the findings made by the primary judge, that there was no miscarriage of justice. If the evidence of Dr Gibbs and Messrs Stavros and Riches were to be accepted at face value, it would certainly be open to a Court to find that Darrell Lea's use of purple is likely to cause the consumer errors identified by Dr Gibbs. That could be sufficient to justify a conclusion that Darrell Lea had engaged in conduct that was likely to mislead or deceive. 50 The Court then addressed Darrell Lea's contention that the disputed evidence would make no difference as it was of "no weight at all". In dealing with that submission, the Court expressed some comments concerning the principles to be applied in the treatment of the evidence which seemed to influence the primary judge in directions subsequently made for the conduct of the further hearing. The comments were these: 102. The primary judge erred in rejecting the disputed evidence in its entirety. That is not to say, however, that there may not have been specific objections to parts of the disputed evidence that could have been taken and should have been upheld. Further, it may be that, on full consideration of the applicability of s 135 of the Evidence Act in relation to the whole of the disputed evidence, all of it would be rejected as involving an undue waste of time in the light of its probative value. 103. … senior counsel for Darrell Lea outlined specific objections to significant parts of the disputed evidence. One such objection was that the affidavits did not demonstrate that the opinions expressed by Dr Gibbs and Messrs Stavros and Riches were based upon their specialised knowledge, as required by s 79 of the Evidence Act. 104. All of Dr Gibbs's conclusions concerning consumer errors appears to be based on the proposition that, merely by using purple in the way described … those errors are likely to result. While Dr Gibbs described in some detail what he meant by the four consumer errors, it is at least arguable that his affidavit does not clearly explain how the use by Darrell Lea of purple in the manner he describes constitutes "use of Cadbury purple". Nor does Dr Gibbs provide any reasoning as to how the particular use of purple by Darrell Lea to which he refers is likely to give rise to the four consumer errors in question. 105. It is not appropriate for the Court, in the circumstances, to express any view about the objections … . Nevertheless, it should not be thought that the Court is expressing any view concerning the admissibility of the disputed evidence, if appropriate specific objections were taken at a new trial. 106. A Court should not act upon opinions, unless the prerequisites of s 79 are satisfied. It must be established, on the balance of probabilities, that the witness who gives an opinion has specialised knowledge, that the specialised knowledge is based on the witness' training, study or experience and that the opinion is wholly or substantially based on that specialised knowledge. Accordingly, there must be evidence explaining both how the opinion stated is said to rest on the specialised knowledge of the witness and how the specialised knowledge is based, wholly or substantially, on the witness' training, study or experience. 107. The evidence in chief of a witness giving opinion evidence must explain how the field of specialised knowledge possessed by the witness, by reason of training, study or experience, and on which the opinion is wholly or substantially based, applies to the facts established or assumed, so as to produce the opinion about which evidence is to be given. If those matters are not made explicit in chief, it would normally not be possible for the Court to make a judgment as to whether the prerequisites of s 79 have been satisfied and whether the evidence is in fact admissible. 108. Further, unless a witness states in his or her evidence in chief the grounds and reasoning that have led to the opinion, the opinion is valueless. Before the Court can assess the value of an opinion, it must know the facts on which it is based. If the opinion is based on irrelevant facts or facts that are clearly not going to be proved, the opinion is likely to be valueless. It should not be for a cross‑examiner to endeavour to elicit the facts or assumptions upon which an opinion is expressed, and it would be unfair to leave such matters to the cross‑examiner. Except in a straightforward, uncomplicated case, where the facts are admitted or otherwise readily identified, opinion evidence would normally be rejected under s 135 if the facts or assumptions upon which the opinion is based are not expressly stated. 109. It is for the Court to judge the reliability of, and the weight to be given to, particular evidence. Opinion evidence, like any other evidence, must be comprehensible and reach conclusions that are rationally based. The process of inference or reasoning that leads to conclusions ought to be stated or revealed in a way that enables the conclusions to be tested and a judgment to be made about their reliability and the weight that should be given to them. If not, the opinion evidence would normally be rejected under s 135. 110. The primary judge rejected the disputed evidence by the application of an incorrect principle. While if proper objections were taken, the disputed evidence might be wholly inadmissible, it may be that such objections could be overcome by eliciting further evidence. It is clearly not appropriate for the Full Court to endeavour to consider what objections could properly have been taken and what objections would be upheld. Cadbury would be entitled to the opportunity of applying for leave to elicit further evidence to overcome such objections. [emphasis added] 51 The Full Court concluded that it could not be said that the disputed evidence was of so little weight that it could not influence the result of a new trial so as to produce a different result [111]. At [112], the Court noted a submission of Cadbury that it would be inappropriate for the proceeding to be remitted to the primary judge. The Court said this: 112. … Cadbury contends that, in the light of comments made by the primary judge in the course of ruling on the admissibility of the affidavit of Dr Gibbs, his Honour expressed views that indicated his Honour no longer has an open mind concerning the weight that should be accorded to the disputed evidence. Cadbury draws particular attention to the observations made by the primary judge that much of the factual material relied upon by Dr Gibbs is vague, tendentious and of little weight. 52 That submission by Cadbury was put by counsel for Cadbury to the Full Court (Black CJ and Emmett and Middleton JJ) in these terms: MR HUTLEY: One of the difficulties produced by his Honour's observation is that, should your Honours order a retrial, an issue should arise whether it should go back before his Honour or to another judge, having regard to his Honour's remarks about this material before he, his Honour, has had an opportunity to see it tested in cross‑examination in the way we submit it ought. … BLACK CJ: His Honour is not saying he'd disbelieve the evidence MR HUTLEY: No, your Honour. But his Honour has made it perfectly clear, without the opportunity of seeing the witness or considering it - in the context of his Honour's attitude to this material - such that, if one looks at it from the point of view of a client who was facing a retrial where the central evidence of the case has been rejected and this Court has found it admissible, a concern, in our respectful submission, could arise of the variety that his Honour had formed a view adverse to Dr Gibbs' evidence which might predispose his Honour to a determination of the matter adverse to our client. Just at an appearance level. Of course I am not suggesting in fact. [emphasis added] 53 The Court noted at [113] that the matters particularly emphasised by Cadbury concerned the criticism of the factual material relied upon by Dr Gibbs as vague, tendentious and of little weight, which conveyed no criticism of the opinion itself. That phrase was a reference to the primary judge's remarks at [25] of the evidence ruling (see [24] of these reasons). The Overview document was criticised at [27] as containing vague and self‑serving statements (see [25] of these reasons). Since the criticism did not go to the opinion itself, it followed [113], according to the Full Court, that there was "no reason to conclude that his Honour would not bring a fair and open mind to the question of the specific objections to the disputed evidence and the resolution of the issues" in light of any of the disputed evidence that might ultimately be admitted consistent with the Court's reasons. Thus, it followed that there was "no reason why the proceeding should not be remitted to the primary judge for further hearing". The Court noted that it followed, as a matter of course, that if the primary judge were to accept that he would not be able to bring an open mind to the resolution of the proceeding having regard to his Honour's previous rulings both on the disputed evidence and in the final decision, "it would be a matter for his Honour to decide whether he considered it was appropriate for the proceeding to be referred to another judge for a retrial ab initio". 54 A number of things should be noted about the passages in the initial reasons of the Full Court from [111] to [114]. First, for the purposes of this appeal, Cadbury says the difficulty of apprehended bias extends to the primary judge's references to the evidence being of "no help at all" and the criticism of "unnecessary intellectualisation" and "part speculation" among the tenor of the remarks generally, not just to the primary judge's criticism that foundation facts relied on by Dr Gibbs were vague, tendentious and of little weight or that the Overview document contained statements that were vague and self‑serving. Secondly, Cadbury says that the Full Court's references to "no reason to conclude" (as quoted) that his Honour would not bring a fair and open mind to the issues to be determined, is a reference to a conclusion as to actual bias and those observations say nothing of apprehended bias. Mr Hutley however put Cadbury's contention (before Black CJ; Emmett and Middleton JJ) as to remittal to a different judge expressly "at the appearance level" and disavowed any "suggestion of [bias] in fact". Cadbury continues to emphatically assert no suggestion of actual bias on the part of the primary judge. The only issue is apprehended bias and that seems to have always been the position. Counsel for Darrell Lea does not contend that [113] and the first sentence of [114] are dispositive of a contention of apprehended bias. That seems to be necessarily so because apart from the submission quoted above, the matter was not expressly dealt with and to now treat the Full Court's observations at those paragraphs as dispositive of apprehended bias would constitute procedural unfairness. Nevertheless, Darrell Lea says the unanimous impressionistic assessment of the judges comprising the Court is both significant and influential upon not only the primary judge but a lay observer acting reasonably looking down upon the observations of three judges of the Federal Court in making such remarks in the context of an appellate election under s 28(1)(c) to remit the matter to the primary judge corrected as to the primary judge's error in rejecting the disputed evidence guided by the principles reflected at [102] to [110]. 55 Accordingly, the Full Court allowed the appeal, set aside the orders of the primary judge and remitted the proceeding to the trial judge for further hearing.

The Full Court's further reasons 56 Consequent upon those orders, Cadbury moved the Court for a variation of the order that the matter be remitted to the trial judge for further hearing and sought an order that the proceeding be remitted to the trial judge for a new trial. Cadbury did not suggest that an order remitting the matter to the primary judge for further hearing was not an order within s 28(1)(c) of the Federal Court of Australia Act 1976. In its further reasons amplifying the earlier reasons the Court affirmed its view that it could not be said that the disputed evidence was of so little weight that it could not influence the result of any trial so as to produce a different result but that the Court did not consider that "a new trial was justified" [6]. Rather, the Court was of the view that "justice would be served by a further hearing before the primary judge at which Cadbury would have another opportunity of adducing the disputed evidence" [6]. As to the basis of the remitter, the Court noted that "it [the proceeding] would be before the primary judge as though the case were part heard" [7]. The primary judge would entertain, determine and make rulings upon objections to the disputed evidence including any "additional or further evidence [that might] be admitted" [7]. That might result in Darrell Lea seeking to adduce "its own evidence in response to the disputed evidence" [7]. The Court noted its earlier observation that if proper objections were taken to the disputed evidence at the further hearing and the evidence were rejected, it would be open to the primary judge to allow Cadbury to elicit further evidence to overcome the objections. The Court said at [8]: That would be an aspect of the management of the further hearing by the primary judge in the same way as it would have been had his Honour not rejected the disputed evidence in its entirety. … If, in the exercise of his discretion, the primary judge were to permit Cadbury the opportunity of adducing further evidence to overcome any objections, that would be a matter entirely for his Honour at the further hearing. 57 The Court noted at [9] the possibility, without expressing any view on the question, that after hearing proper objections from Darrell Lea, none of the disputed evidence might be admitted or that the primary judge "would still reject the disputed evidence under s 135 of the Evidence Act". Those matters, including the exercise of discretion under s 135, were "entirely a matter for the primary judge" [9]. As to the conduct of the further hearing, the Court at [10] and [12] said this: 10. Further, there would be no reason why the primary judge should entertain any contention that he should reverse earlier rulings made by him that were not in any way dependent upon the rejection of the disputed evidence. His Honour should be in a position to conduct the further hearing as though he had admitted such of the disputed evidence as his Honour finds to be admissible after considering appropriate objections. 12. Similarly, if the primary judge were persuaded that the conduct of the hearing to date was such that the admission of any part of the disputed evidence that his Honour was disposed to admit would cause injustice, it would be a matter for his Honour as to whether the trial should, for that reason, be aborted. The primary judge should be regarded as being in the same position as he would have been in had he not made the ruling of 31 March 2006. 58 Cadbury's motion for an order for a retrial was thus dismissed.

The motion before the primary judge for disqualification 59 Cadbury brought on a motion seeking an order that the primary judge disqualify himself from further hearing the matter on the ground of apprehended bias. The application was dismissed (Cadbury Schweppes v Darrell Lea (No. 5) [2007] FCA 1245; (2008) 240 ALR 780 (the disqualification ruling)). Cadbury contends in this appeal that the primary judge made evident in his reasons for refusing to disqualify himself that he had been reinforced to a considerable degree in his original evidence ruling by observations of the Full Court and thus the primary judge has not embraced the correction of his earlier error in an unqualified way. It is therefore necessary to examine the primary judge's reasons for refusing disqualification, a little closely. The primary judge noted his earlier reliance upon R v Turner [1975] QB 834 and Transport Publishing (supra) in rejecting the evidence of likely consumer selection choices as the evidence dealt with matters not outside the experience and knowledge of a lay tribunal [8]. The primary judge expressed regret that "this reasoning overlooked the 'critical point', namely, s 80(b) of the Evidence Act" [9] and [17] and that unfortunately the provision was not drawn to his Honour's attention [9]. The primary judge noted at [10] his earlier references to Cat Media (supra), Domain Names v .au Domain Administration (supra) and the extract from Cross on Evidence. His Honour seemed to be suggesting that there was uncorrected foundation in the common law for the approach his Honour had adopted but that s 80(b) of the Evidence Act now rendered such evidence admissible. At [11], the primary judge noted that he had made: some critical comments about the value of Dr Gibbs' evidence (although not of course anything about him personally, or his standing in the field), and quoted paras [23] to [31] of his evidence ruling in full. Those paragraphs contain the references which are criticised. Paragraphs [29], [30] and [31] set out the policy considerations addressed by his Honour. The primary judge also quoted at [13] paras [96] to [112] of the trial judgment which contain the specific trial findings. 60 The primary judge noted his earlier ruling that had the evidence of Dr Gibbs been admissible he would have rejected it, in any event, in the exercise of discretion under s 135 and noted his criticism in the evidence ruling of the Overview document prepared by Cadbury's solicitors [19]. His Honour noted the Full Court's view that those criticisms did not extend to the Basic Principles and Background Issues section of Dr Gibbs's opinion [20]. The primary judge noted the Full Court's observation that his Honour's criticism of Dr Gibbs for assuming the colour purple used by Darrell Lea was similar to that used by Cadbury was ultimately at odds with the primary judge's findings that Darrell Lea in fact used a purple much like that used by Cadbury [21]. The primary judge noted the Full Court's view that Dr Gibbs's evidence could have a significant bearing on a judge's understanding of human behaviour and consumer information‑processing errors and that the evidence had some probative value within the meaning of s 135 [22]. The primary judge noted the concession on the earlier appeal of Cadbury as to particular findings being open and rational (absent the disputed evidence) and that that concession was based upon the "truncated evidence" [24]. His Honour also noted the Full Court's view that if the evidence of Dr Gibbs and Messrs Stavros and Riches were accepted at face value it would "certainly" be open to a Court to find that Darrell Lea's use of purple is likely to cause the consumer errors identified by Dr Gibbs [25] and thus conduct on the part of Darrell Lea that was likely to mislead or deceive. The primary judge noted the reliance by counsel for Darrell Lea on the Full Court's observations in its initial reasons at [111] to [114] and in particular [113]. The primary judge noted that the remittal of the matter to him for further hearing would involve a reconsideration of the exercise of the discretion under s 135. The primary judge then set out in full paras [5] to [12] of the Full Court's further reasons. 61 The primary judge noted the written contentions of Cadbury. Cadbury contended that a fair minded observer might reasonably conclude that the primary judge when embarking upon the further hearing would do so holding a view that Cadbury's claims in the proceeding are "untenable"; that the primary judge held a view that the evidence of Dr Gibbs and Messrs Stavros and Riches "should not be admitted in the further hearing"; that the primary judge "might not pay proper regard to the excluded evidence if admitted and would not bring an impartial and unprejudiced mind to the exercise of the discretion under [the Evidence Act]"; that the primary judge would not approach objections "with impartiality"; and that "faced with the almost inevitable prospect of having to recuse himself if the expert evidence is admitted, 'human weakness' might lead the trial judge 'to circumvent [an apprehension of bias] by taking the opportunity to uphold any form objections or s 135 objections'". 62 The primary judge also noted oral submissions by counsel for Cadbury that no allegation of actual bias was made by Cadbury [33]; that Cadbury's essential point was that the primary judge having expressed himself "strongly" on aspects of the case that would need to be re‑heard, a reasonable apprehension arose in the mind of the fictitious reasonable observer that the primary judge would not be able to bring an impartial mind to bear on the "vexed question of the expert evidence" [33]; and that significant argument would arise concerning the admissibility of the evidence of Dr Gibbs and other experts, additional objections having been foreshadowed by Darrell Lea [34]. There would also be further argument over the possible exclusion of evidence in the exercise of discretion under s 135 [34]. The primary judge noted that counsel for Cadbury placed emphasis upon the evidence of Ms McGlinchey and how Darrell Lea came to adopt the colour purple in the years 2000 to 2004. Counsel for Cadbury contended that at a final hearing [e.g. the further hearing giving rise to a final hearing] Cadbury "may well seek to put to witnesses, previously cross‑examined, matters arising from the expert evidence previously excluded". The primary judge observed at [37] that Cadbury had not explained how expert opinion evidence might be put to a witness on the issue of fact of the intention or belief of that witness in adopting the use of the colour purple at Christmas 2000. The primary judge also noted that Mr Houghton QC, counsel for Cadbury, had acknowledged the difficulty of the utility of the evidence on that issue by conceding "we don't say that's our best point". The primary judge agreed that it was not. 63 The primary judge approached the ultimate question in this way. 64 The hypothetical lay observer must be credited with knowledge not only of the primary judge's remarks in the evidence ruling and the trial judgment but with the observations of the Full Court in its initial and supplementary reasons. In that sense, the fair minded lay observer is not a person wholly uninformed about the law in general or the particular issue to be decided. At [40], the primary judge said this: The lay observer would be aware that Cadbury had criticised the remarks in question, and had on two occasions sought a trial de novo before another judge. The lay observer would understand that the Full Court saw no problem in having the matter further considered by me. In particular, the observer would consider what the Full Court said in its second judgment at [112] - [114] [note, that that reference should be a reference to the Full Court's first judgment at those paragraphs] quoted above and the observation of Emmett J, speaking for the Court, in the course of argument [which is a reference to Emmett J's observation that the use of the phrase "further hearing" rather than a new trial was adopted advisedly, and may involve a reconsideration of the exercise of the discretion under s 135 of the Evidence Act]. 65 His Honour considered that the lay observer in objectively looking at criticisms of the utility of "expert opinion in consumer cases" made by the primary judge on policy grounds would see, from reading the initial reasons of the Full Court, that similar criticisms had been expressed by other judges of the Federal Court of Australia; those criticisms had been referred to by the Full Court in the present case and not disapproved [41]. At [42], his Honour said that the observer would also see that whilst "critical comments on some aspects of Dr Gibbs' evidence" had been made, those comments "read as a whole and in context" revealed that "the real thrust of the remarks in the evidence ruling was concerned with the effects of expert evidence of this kind in this kind of case, in other words with the policy rationale for what the judge thought the law to be - wrongly as it turned out" [42] [emphasis added]. The primary judge, speaking of himself, made these further remarks at [42] and [43]: 42. Regrettably, the primary judge proceeded upon the assumption that this evidence would not be admissible at common law, an assumption which the Full Court accepted (the heading of s 80 tells us "Ultimate issue and common knowledge rules abolished"). The primary judge should have been aware of s 80(b), and counsel should have directed his attention to it. Judges, like other citizens, do not always agree with laws. But judges have to administer the law as it stands. The observer would think, as did the Full Court, that this will happen in the present case. 43. Of course there are practical problems. The reasonable lay observer would recognise the difficulty of a judge's task in taking into account new evidence when he or she has already reached a decision on a great deal of other evidence, including, although not limited to, evidence going to the same issues as the wrongly excluded evidence. But that is inherent in the power given by s 28(1)(c) of the [Federal Court Act 1976] which gives explicit powers to Full Courts to do what the Full Court has done in the present case. [emphasis added] 66 As to [43] above, of course, there is nothing inherent in the power conferred on the Court by s 28(1)(c) that would enable the Court to sanction, by remitter, the exercise of judicial power by the primary judge in any further hearing or re‑trial should the judge's conduct of the proceeding be affected by apprehended bias. The question is whether, in the circumstances of the case, the determinations already made by the primary judge in the context in which they were made, suggest pre‑judgment of the issues to be determined upon remitter.

The procedural directions 67 In an unsuccessful application to file a notice of contention before the earlier Full Court, Darrell Lea outlined detailed objections to significant parts of the disputed evidence which in part led to the Full Court's observations at [103] to [110] of the initial reasons and the remarks at [7] to [9] of the further reasons (see [43] and [44] of these reasons). 68 The primary judge seemed to accommodate a procedural process for dealing with objections to the disputed evidence foreshadowed by the notice of contention and the reception of additional evidence as contemplated by the Full Court. The primary judge granted leave to Cadbury to amend its statement of claim; required Darrell Lea to provide Cadbury with a statement of all objections to the disputed evidence; gave leave to Cadbury to supplement its evidence and address Darrell Lea's objections; gave Darrell Lea leave to file material in reply; and allocated five sitting days for the further hearing (the initial trial having taken 12 sitting days). Those orders resulted in further material filed by Cadbury consisting of a further affidavit from Mr Stavros sworn 24 August 2007 (47 pages) with two short exhibits; a further affidavit of Dr Gibbs sworn 28 August 2007 (76 pages); and a further affidavit of Mr Riches sworn 28 August 2007 (45 pages) together with a short exhibit (see AB, Part C, pp 137 to 316).

The essential principles 69 The principles are these. 70 The basic principle upon which the common law system of adversarial trial rests is that the Tribunal is independent and impartial. So important is the principle that even "the appearance of departure from it is prohibited lest the integrity of the judicial system be undermined" (Ebner v Official Trustee in Bankruptcy (2000) 205 CLR 337 at [7], per Gleeson CJ, McHugh, Gummow and Hayne JJ ("Ebner")). The apprehension of bias principle finds expression in this test (Ebner at [6]) (leaving aside any question of waiver or necessity): … a judge is disqualified if a fair‑minded lay observer might reasonably apprehend that the judge might not bring an impartial mind to the resolution of the question the judge is required to decide. 71 That test speaks of possibilities rather than probabilities and contemplates a "real and not remote" possibility that a judge might not bring an impartial mind to bear. The test recognises the possibility of human frailty in decision‑making. The application of the test requires two things. First, the identification of what it is that might lead a judge to decide the particular questions before him or her other than on the merits. Secondly, having identified the factor or circumstance that might influence a departure from meritorious decision‑making, it is "no less important" (Ebner at [8]) to articulate the "logical connection" between that factor and the fear that the judge might not apply proper judicial method (that is, merits based decision‑making) in resolving the controversy on the facts and the law (Ebner at [8]: as to a recent example of the application of the second limb, see: Expectation Pty Ltd v PRD Realty Pty Ltd & Anor (No. 2) (2006) 151 FCR 160). Only when the relevant factor is identified and the logical connection articulated, can the reasonableness of the asserted apprehension of bias be assessed. This test reflects (Ebner at [33]): … the general principle to be applied … to problems of apprehended bias, whether arising from interest, conduct, association, extraneous information or some other circumstance. 72 Ebner (comprising two appeals) was a case involving contended "interest" on the part of the primary judge through relatively small shareholdings in a major Australian bank held both directly in one case and through a family trust in another which, although disclosed, was said to give rise to apprehended bias in the determination of the issues. Johnson v Johnson (2000) 174 ALR 655 was a "conduct" case in which the primary judge during the course of a lengthy hearing concerning the distribution of substantial assets between a husband and wife consequent upon dissolution of the marriage, twice made a particular observation that was said to suggest pre‑judgment (e.g. apprehended bias) as to the reliability or credit of the applicant husband. Gleeson CJ, Gaudron, McHugh, Gummow and Hayne JJ at [12] emphasised three things. First, reference to the hypothetical fair‑minded lay observer makes plain the entirely objective character of the test. Secondly, the observer is taken to be "reasonable". Thirdly, applying an observation of McHugh J in Vakauta v Kelly (1988) 13 NSWLR 502 at 527 adopted by Toohey J in Vakauta v Kelly (1989) 167 CLR 568 at 584‑5, the Court noted that: The person being observed is a professional judge whose training, tradition and oath or affirmation require [the judge] to discard the irrelevant, the immaterial and the prejudicial. 73 Further, the fictional observer is not presumed to have a detailed knowledge of the law, or the character, history or ability of a particular judge. Nevertheless, the reasonableness of any suggested apprehension of bias is to be considered in the context of "ordinary judicial practice" (Johnson v Johnson at [13]). The rules and conventions governing such practice take account of the "exigencies of modern litigation". Sometimes modern case management will result in a dialogue between the judge and counsel which might suggest an impression as to the judge's view of the strengths or weaknesses of a party's case on a particular issue. Opinions (although tentative or preliminary) are very like to be formed yet participants in these processes understand that justice will be done between the parties because a judge applying the professional standards previously mentioned will ultimately decide issues on the merits by discarding the irrelevant, the immaterial and the prejudicial so as to reach a decision on the merits according to law. Sometimes, statements made or the behaviour of a judge may create "an ineradicable apprehension of pre‑judgment" (Johnson v Johnson at [14]). However, later statements or later behaviour or both taken together, may alter an impression of pre‑judgment as, objectively viewed, "the hypothetical observer is no more entitled to make snap judgments than the person under observation" (Johnson v Johnson at [14]). 74 The lay observer must be "fair‑minded" and act out of reason and thus act "reasonably". In order to act out of reason, the lay observer must have a frame of reference so as to make not just any decision but an informed decision and thus a reasoned decision. Plainly, the lay observer is not informed by a "detailed knowledge" of the law or by a knowledge of the values or expertise of the particular judge. Nor is the lay observer to be attributed with "undue knowledge and sophistication" (Johnson v Johnson at [42], per Kirby J) or "highly specialised knowledge" or "all that was eventually known to the court" (Johnson v Johnson at [49], per Kirby J). Yet, the fictitious bystander is not "wholly uninformed and uninstructed about the law in general or the issues to be decided" (Johnson v Johnson at [53], per Kirby J). At [53], Kirby J also said this: The attributes of the fictitious bystander to whom courts defer have therefore been variously stated. … Being reasonable and fair‑minded, the bystander, before making a decision important to the parties and the community, would ordinarily be taken to have sought to be informed on at least the most basic considerations relevant to arriving at a conclusion founded on a fair understanding of all the relevant circumstances. The bystander would be taken to know commonplace things, such as the fact that adjudicators sometimes say, or do, things they might later wish they had not, without necessarily disqualifying themselves from continuing to exercise their powers. The bystander must also now be taken to have, at least in a very general way, some knowledge of the fact that an adjudicator may properly adopt reasonable efforts to confine proceedings within appropriate limits and to ensure that time is not wasted. The fictitious bystander will also be aware of the strong professional pressures on adjudicators (reinforced by the facilities of appeal and review) to uphold traditions of integrity and impartiality. Acting reasonably, the fictitious bystander would not reach a hasty conclusion based on the appearance evoked by an isolated episode of temper or remarks to the parties or their representatives which was taken out of context. Finally, a reasonable member of the public is neither complacent nor unduly sensitive or suspicious. [emphasis added] 75 Such a bystander informed of the basic considerations relevant to this case in reaching a conclusion founded on a fair understanding of all the relevant circumstances would be taken to know and weigh in the balance these things. First, the primary judge rejected the disputed evidence fundamentally on the ground that it went to matters which in the primary judge's view, did not fall outside the knowledge or experience of ordinary persons as it dealt with consumer decisions concerning the purchase of low cost everyday items of chocolate confectionary. Secondly, the reasons identified by the primary judge in the evidence ruling make plain that the primary judge accepted "without doubt" that the science of human behaviour, Dr Gibbs's discipline, is an area of specialised knowledge and that no disrespect was intended or given to Dr Gibbs or the other expert witnesses by the primary judge's thinking on the issue of admissibility. 76 Thirdly, that thinking was directed to an assessment of the questions in the controversy as ones "quintessentially of fact" within the experience of the trier of fact. Fourthly, the primary judge made an error in refusing to admit the evidence, an error common to the judge and counsel for the parties as no mind was turned to the implications of s 80(b) of the Evidence Act. However, the Full Court corrected that error of law and the primary judge although comforted by his understanding of the common law position, recognised the error of law on his part in failing to apply the provision of the Evidence Act and admit the opinion evidence. 77 Fifthly, although Cadbury contends that the primary judge's explanation for refusing to disqualify himself from conducting the further hearing compounds the earlier error and fails to accept in an unqualified way the correction of error, a proper balanced objective reading of his Honour's reasons demonstrates a thorough application of the Full Court's reasons and an unqualified willingness to apply the law and test both the admissibility of the evidence according to whatever proposition might be advanced as to admissibility and, if admitted, weigh the evidence in the balance according to the merits. 78 Sixthly, the error was an error as to admissibility of opinion evidence, made by reason of what his Honour thought to be the prevailing common law provision and thus the governing principles to be applied as to admissibility. At no time has the primary judge presided over a hearing where the evidence was admitted, tested, applied and findings made either in reliance upon or in rejection of the evidence of the experts. 79 Seventhly, the lay observer would also understand that the reference to the evidence of Dr Gibbs as "not helpful at all" reflects a conclusion that since the evidence goes to questions of fact par excellence and thus matters not outside the knowledge of ordinary persons, the trial would be influenced in a way which his Honour described as "greatly complicated" and "lengthened" by broader disputation and the calling of opposing experts. That view was not a judgment about the substantive evidence or the experts individually as the evidence was never before the primary judge in the full evaluative sense of material that may or may not be probative of facts in issue. 80 Eighthly, the lay observer would be informed of the criticisms the primary judge made for the purposes of s 135 of the Evidence Act of aspects of the opinion evidence. The lay observer being fair‑minded and acting reasonably founded on a fair understanding of all the relevant circumstances would take into account that the primary judge, when expressing those views, was expressing criticism of the foundation facts relied upon by Dr Gibbs and the ultimate probative value of the evidence in the exercise of a discretion. The lay observer's view would also be influenced by the Full Court's observations, without necessarily understanding the sequence of reasoning, that the evidence if admitted could have a significant bearing on a judge's understanding of consumer behaviour and, more significantly, Dr Gibbs's opinions on consumer information processing errors could bear on the questions to be decided and could be of probative value. Moreover, the lay observer would be informed that the Full Court had said that if the evidence were to be admitted and accepted at face value, it would certainly be open to a court to find that Darrell Lea's use of purple is likely to cause the consumer errors identified by Dr Gibbs and thus justify, at face value, a conclusion that Darrell Lea had engaged in conduct likely to mislead and deceive. The lay observer would be informed that such evidence went to information processing errors not Ms McGlinchey's state of mind when adopting a similar colour purple to Cadbury purple. 81 Ninthly, the lay observer would recognise that the Full Court had corrected the error of the primary judge and had laid down a number of principles usefully informing the treatment to be adopted in relation to aspects of the disputed evidence and evidence of the class of the disputed evidence in cases of the kind before the primary judge. Tenthly, the lay observer would recognise that the judge according to professional tradition, training, discipline and commitment to the oath of office would act according to the correction of error and apply the principles articulated by the Full Court. 82 Finally, the lay observer would recognise that the primary judge made a series of directions orders for the management of a further hearing and set aside five days to deal with all of the issues and determine questions to be decided according to the application and weight of the evidence admitted before him. 83 A number of further matters should be mentioned. 84 First, as to Ms McGlinchey, there is no doubt that Mr Myers QC on behalf of Cadbury vigorously put to Mr McGlinchey Cadbury's case that Ms McGlinchey had adopted the particular shade of purple consciously and for the purpose of appropriating Cadbury's reputation. The failure to admit the evidence did not prejudice the putting of propositions to Ms McGlinchey about her state of mind in adopting the course of conduct in issue. 85 Secondly, the lay observer might be confused about the implications of the Full Court's reasons in remitting the matter to the primary judge for further hearing. The lay observer would be very likely to assume that the Full Court's election to remit the matter to the primary judge in the context of the statements made at [113] and [114] of the initial reasons and [7] to [12] of the further reasons (see [4] and [43] and [44] of these reasons), suggests to his or her mind that the Full Court thought that the primary judge could bring an impartial and independent mind to bear in the determination of the issues before him proceeding "as though he had admitted such of the disputed evidence as his Honour finds to be admissible after considering appropriate objections" and regarding himself as "being in the same position as he would have been in had he not made the ruling of 31 March 2006". True it is that the question of whether the primary judge might be satisfied as to whether it was appropriate for him to conduct the further hearing or for another judge to undertake a retrial ab initio, was left to the primary judge to determine and in that sense the lay observer would understand that there was a residual question to be decided. The lay observer would be likely to conclude, adopting a construct, that the Full Court thought that in the absence of the primary judge concluding that he could not conduct the hearing impartially, expressions of opinion by the primary judge concerning the admissibility of the evidence (and factors influencing the exercise of discretion) did not give rise to apprehension of bias. The lay observer, however, would be advised, as Darrell Lea accepts, that the decision of the Full Court in remitting the matter to the primary judge did not carry with the remitter a decision that no question of apprehended bias might arise. The lay observer would test the question according to the matters indicated at [62] to [72]. 86 Thirdly, emphasis is placed by Cadbury upon Livesey v The New South Wales Bar Association (1983) 151 CLR 288. However, in Livesey, two members of the Court of Appeal comprised the Court in the determination of the issues concerning Mr Livesey when on a previous occasion those two members comprised the Court in proceedings concerning Ms Wendy Bacon. Adverse findings of the strongest possible kind were made against Ms Bacon. Ms Bacon was to be called as a witness in the Livesey proceedings. Since very damaging credit findings had been made in relation to Ms Bacon in connection with the very facts and circumstances lying at the centre of the events concerning Mr Livesey, the High Court concluded, unremarkably, that a fair‑minded observer might entertain an apprehension of bias in the Livesey proceedings by reason of the pre‑judgment of the issues of credibility in connection with Ms Bacon. Similarly, in Vakauta v Kelly (1989) 167 CLR 568, the primary judge made pejorative remarks during the course of the hearing concerning the expertise or reliability of professional opinions of expert medical witnesses to be called by the defendant (insurer) describing them as "that unholy trinity" and the "usual panel of doctors who think you can do a full week's work without any arms or legs" and experts whose "views are almost inevitably slanted in favour of the GIO by whom they have been retained, consciously or unconsciously". Those statements made in the course of the hearing were "revived" by what the primary judge said in his reserved judgment. Thus the lay observer would have seen the derogatory and wide‑sweeping references to the particular expert as indicating that the primary judge was concerned to vindicate in the judgment his pre‑conceived and very strong adverse views and had allowed those views to prejudice his whole approach to the case to the detriment of the defendant. 87 The primary judge in this case did not consider the evidence in the resolution of the issues and formed no view of the kind described in Vakauta v Kelly. Cadbury placed considerable emphasis upon the decision of the New South Wales Court of Appeal in Baulkham Hills Shire Council v Basemount Pty Ltd & Anor [2003] NSWCA 189; 126 LGERA 339. In that case, the Court of Appeal (Tobias JA; Handley JA and Ipp JA agreeing) concluded that a reasonable apprehension of bias on the part of the Commissioner arose on the footing that the Commissioner would not be able to decide the questions remitted to her, impartially, as she had, in reaching the initial decision the subject of the appeal, made findings on the evidence in circumstances where she had denied procedural fairness to a party. Statements of principle in that case concerning the objective inability of the Commissioner to determine questions of fact on remitter having previously decided questions of fact during the course of the initial hearing should be viewed with some caution in a case where the fair‑minded lay observer acting reasonably would be mindful that in the present case there was no suggestion of a denial of procedural fairness on the part of the primary judge. In fact, the primary judge conducted an exhaustive hearing in relation to the admissibility of the evidence and delivered published reasons in relation to that matter. 88 Having regard to all of these considerations, it seems to me that the fictitious fair‑minded lay observer is not a person who might reasonably apprehend that the primary judge might not bring an impartial and unbiased mind to the resolution of the questions he was required to decide at the further hearing. 89 Accordingly, the appeal in relation to grounds 1 and 2 of the notice of appeal must be dismissed.

I certify that the preceding seventy-six (76) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Greenwood.

ON APPEAL FROM A SINGLE JUDGE OF THE FEDERAL COURT OF AUSTRALIA

REASONS FOR JUDGMENT BESANKO J 90 This is an appeal from an order made by a judge of this Court on 11 April 2008. The judge made an order dismissing the appellant's application. There are 17 grounds of appeal, but only the first two grounds are presently before this Court. On 5 August 2008, the Chief Justice made orders which have the effect of requiring this Court to hear the first two grounds of the appeal before the other grounds. 91 The first two grounds of appeal are as follows: 1. The learned primary judge erred in refusing to disqualify himself from continuing to hear and determine the proceeding. 2. The learned primary judge ought properly to have concluded that a fair-minded lay observer might reasonably apprehend that the learned primary judge might not bring an impartial and unprejudiced mind to the resolution of the questions which he was required to decide on the further hearing, including the ultimate question: did the respondent by its use of purple in the conduct of its chocolate confectionery business engage in misleading or deceptive conduct in contravention of s 52 of the Trade Practices Act 1974 and/or passing off (the "ultimate question") (the "apprehension of bias"). 92 The proceeding has a long history. On 31 March 2006, the primary judge heard and determined an application by the appellant to adduce certain expert opinion evidence at the trial and the respondent's objection to the receipt of that evidence. The primary judge decided not to admit the evidence and he delivered reasons for his decision: Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (2006) 228 ALR 719. I will refer to this decision as the evidence ruling. 93 On 27 April 2006, the primary judge delivered his decision on the appellant's application. He decided that the application should be dismissed: Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (2006) 229 ALR 136. I will refer to this as the primary judge's substantive judgment. 94 The appellant appealed to the Full Court of this Court against the primary judge's substantive judgment. One ground of appeal involved a challenge to the evidence ruling. The Full Court decided that the primary judge had erred in the course of the evidence ruling and, on 21 May 2007, the Court allowed the appeal and made an order remitting the matter to the primary judge for "further hearing": Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (2007) 159 FCR 397. I will refer to these reasons as the Full Court's reasons. 95 The Full Court rejected a submission by the appellant that the matter should be remitted to a judge other than the primary judge. It seems that, as a result of some observations made by the primary judge at a further directions hearing about the nature and scope of the further hearing, the appellant moved the Full Court to vary its previous order to provide that the matter be remitted to the primary judge for "a new trial". That application was refused, and the Full Court delivered reasons for that decision: Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (No 2) [2007] ATPR 42-175. I will refer to these reasons as the Full Court's further reasons. 96 The appellant then applied to the primary judge for an order that he disqualify himself from hearing the proceeding on the ground of apprehended bias. The application was based on certain observations and conclusions of the primary judge in the evidence ruling and the primary judge's findings of fact and conclusions in the substantive judgment. The primary judge refused the application and delivered reasons for his decision: Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (No 5) (2007) 240 ALR 780. I will refer to these reasons as the disqualification reasons.

The appellant's application and the decision on the application 97 In its application, the appellant claimed that it had a substantial and valuable reputation and goodwill in Australia in the colour Cadbury purple. It claimed that the respondent, by its conduct, wrongfully appropriated and converted for its own use in its confectionery business, the appellant's reputation and goodwill in that colour. The appellant claimed that the respondent had contravened s 52 of the Trade Practices Act 1974 (Cth) ("Trade Practices Act") or s 53(c) or (d) of that Act by making various representations in the course of trade or commerce which were untrue. It is not necessary for present purposes to set out the alleged representations; it is sufficient to say that the effect of the alleged representations was that the respondent represented that its confectionery products had a licence from, or the sponsorship, or approval of the appellant, or that there was a connection or affiliation, association, arrangement or endorsement with, or from, the appellant. The appellant claimed that the same conduct by the respondent which gave rise to contraventions of the Trade Practices Act also amounted to the commission of the tort of passing off. The appellant claimed that the respondent had gained a benefit as a result of its conduct, or that it had suffered loss and damage as a result of the respondent's conduct. 98 In support of its case, the appellant sought to adduce expert opinion evidence from three witnesses directed to a number of matters, including the effect of the respondent's conduct on consumers of chocolate confectionery. Those witnesses were Dr Brian Gibbs, Mr Constantino Stavros and Mr Timothy Riches. Dr Gibbs is Associate Professor of Marketing and Behavioural Science in the Melbourne Business School at the University of Melbourne, Mr Stavros is Senior Lecturer in the School of Economics, Finance and Marketing of RMIT University, Melbourne, and Mr Riches is the managing director of FutureBrand FMA Pty Ltd, a branding and design consultancy within the world's largest marketing services group. A summary of the evidence the appellant sought to adduce from Dr Gibbs is set out in the primary judge's evidence ruling (at 721-722 [5]) and in the Full Court's reasons (at 402-408 [19]-[39]). There is also a summary of Dr Gibbs' proposed evidence in the reasons for judgment of Greenwood J on this appeal, which I have had the advantage of reading (at [32]-[33]). In my reasons, I will refer to the evidence that the appellant sought to adduce from Dr Gibbs and Messrs Stavros and Riches as the disputed evidence. 99 In the evidence ruling, the primary judge decided that Dr Gibbs' expert opinion evidence was not admissible. He referred to s 76 and s 79 of the Evidence Act 1995 (Cth) ("Evidence Act"). His Honour said that Dr Gibbs' opinions were about matters which were within the knowledge or experience of ordinary persons. Alternatively, the opinions were about, or concerned, ordinary human nature and were inadmissible on that ground. In the latter context, he referred to the observations of Dixon CJ, Kitto and Taylor JJ in Transport Publishing Co Pty Ltd v The Literature Board of Review (1956) 99 CLR 111 at 119. 100 The primary judge said that, in the alternative, if Dr Gibbs' opinions were admissible, he would exercise the Court's general discretion in s 135 of the Evidence Act to exclude Dr Gibb's evidence. He expressed certain conclusions about the probative value of Dr Gibbs' evidence and a conclusion about the undue waste of time which might result from the admission of his evidence. In exercising the discretion to exclude Dr Gibbs' evidence, the primary judge relied on s 135(c), that is to say, he relied on his assessment that the probative value of the evidence was substantially outweighed by the danger that the evidence might cause or result in undue waste of time. Towards the end of his reasons for the evidence ruling, the primary judge identified what he said were some important policy considerations against the adducing of the type of evidence Dr Gibbs proposed to give, although he made it clear that he did not suggest that the policy considerations were within the "specific discretionary factors" in s 135. A more detailed examination of the primary judge's reasons on the evidence ruling will be necessary and that appears later in these reasons. 101 The primary judge ruled that the evidence of Messrs Stavros and Riches was inadmissible on the same ground that he had ruled that Dr Gibbs' evidence was inadmissible, although, in the cases of the evidence of Messrs Stavros and Riches, he did not express an opinion on how, if it had been necessary to do so, he would have exercised the general discretion in s 135 of the Evidence Act to exclude evidence. 102 The primary judge heard the proceeding and delivered his substantive judgment. The key findings of fact made by the primary judge were as follows (at 154-155 [96]-[112]): 96. There is wide awareness among Australian consumers of the use by Cadbury of a dark purple colour: (i) in connection with the marketing, packaging and presentation of certain chocolate products, particularly Cadbury Dairy Milk and other block milk chocolate products; and (ii) as a corporate colour. 97. Cadbury does not have an exclusive reputation in the use of this dark purple colour in connection with chocolate. Other traders have, with Cadbury's knowledge, for many years used a similar shade of purple. Cadbury has not consistently enforced its alleged exclusive reputation. In relation to its chief competitor Nestlé, Cadbury has, for its own commercial reasons, permitted a use of purple in relation to popular chocolate products. 98. Cadbury markets many chocolate products which have little or no purple in their packaging. 99. Cadbury products, regardless of the presence or absence of purple in the packaging, always bear the Cadbury name in a distinctive script. 100. Cadbury's use of purple in marketing advertising and promotion is, and is seen by consumers to be, inextricably bound up with the well-known name "Cadbury" in its distinctive script. Cadbury never uses the colour purple in isolation as an indicium of trade. 101. Cadbury products, with insignificant exceptions, are not sold at retail level at premises owned or occupied by Cadbury. 102. Cadbury's marketing of chocolate heavily emphasises specific products and, in particular, Cadbury Dairy Milk block chocolate. 103. "Darrell Lea" is a name well-known in connection with chocolate in those parts of Australia where it operates, even though not as well-known as Cadbury. 104. The names "Darrell Lea" and "Cadbury" are quite distinct in sound and appearance (especially with the respective scripts the parties have adopted) and not likely to be mistaken for each other. 105. Darrell has, since at least Christmas 2000, used in its marketing, packaging, promotion and point of sale presentation a purple colour much like that used by Cadbury. There has been particular use at Christmas 2000 to 2004 inclusive and also uses at other times. Such usage has diminished and purple has been to a significant extent replaced by blue since 2004. 106. Darrell Lea did not adopt the colour purple with the intention of leading consumers to believe its products were Cadbury products or that it, or its products, had some kind of association with Cadbury. 107. Most of Darrell Lea's retailing occurs in premises which its owns or occupies. Other retailing occurs from separate stands or displays in retail premises, such as newsagents, pharmacies, convenience stores and video stores. Darrell Lea has only a minor presence in supermarkets and only, in the past, to a very limited and transient extent in the major chains. Its products are not presented for sale in close proximity to Cadbury's. 108. Darrell Lea's marketing gives less emphasis to particular products than does Cadbury. 109. Darrell Lea does not sell moulded block chocolate. 110. Darrell Lea uses its name in a distinctive script widely and consistently in marketing, packaging and point of sale presentation. 111. Colour recognition or attraction can play an important part in consumer decisions to purchase chocolate. 112. Consumer decisions to purchase chocolate are often made quickly and on impulse but not necessarily irrationally. Price and brand recognition can play an important part. 103 His Honour's finding in [106] above was based, or largely based, on evidence called by the respondent from one Ms Anne McGlinchey. At the relevant time, she was the respondent's marketing manager, and she gave evidence as to how the respondent came to use the colour purple at Christmas in the years 2000-2004. His Honour accepted Ms McGlinchey as a witness of truth and he accepted her evidence that, in deciding that the respondent should use purple in connection with its confectionery products, she did not have an intention to associate the respondent with the appellant, or to copy the appellant. 104 Having regard to his findings, the primary judge said that he was not satisfied that the respondent's use of the colour purple conveyed to the reasonable consumer the idea that it, or its products, had some connection with the appellant. Accordingly, he dismissed the appellant's application.

The appellant's appeal to the Full Court 105 On the appellant's appeal, the Full Court held that the primary judge had erred in concluding that Dr Gibbs' expert opinion evidence was not admissible because his opinions related to matters within the knowledge or experience of ordinary persons. The Full Court noted that the primary judge had not referred to s 80(b) of the Evidence Act. The Full Court further noted that although the primary judge had indicated in relation to Dr Gibbs' evidence that, in the alternative, he would exercise the general discretion in s 135 of the Evidence Act to exclude the evidence, he had not addressed the exercise of the general discretion in the cases of the evidence of Messrs Stavros and Riches. In those circumstances, the Court said (at 413 [68]) that "there is no utility in considering whether the putative exercise of the discretion by his Honour in relation to Dr Gibbs' evidence would have involved a miscarriage of the discretion". However, the Court did make certain observations on the exercise of the general discretion by the primary judge. It is not necessary to set out those observations in any detail. It is sufficient to say that the Full Court suggested that the primary judge might have erred in his assessment of the probative value of Dr Gibbs' expert opinion evidence in that the evidence might have had more probative value than the primary judge considered it had. In addition, the Full Court said that the primary judge may not have assessed, or assessed adequately, the additional time likely to result from the admission of the evidence. 106 The Full Court said that a number of the primary judge's findings, that is, those set out at [96], [100], [103], [104], [105], [111], [112] of the substantive judgment and set out above ([102]) might be influenced by Dr Gibbs' evidence. 107 The Full Court said that, if the primary judge had in fact been right to reject the evidence of Dr Gibbs and Messrs Stavros and Riches, the appellant had not demonstrated any error in the primary judge's substantive judgment. 108 The Full Court also considered a submission by the respondent that there was no miscarriage of justice because, inter alia, the disputed evidence was of so little weight that, even if admitted, it could not affect the outcome of a new trial. The Court rejected the submission, saying that it could not be said that the disputed evidence was of so little weight that it could not influence the result of a new trial. Having said that, the Full Court accepted that, on the further hearing, the primary judge might uphold specific objections to the disputed evidence which the respondent wished to agitate, or even exclude it in its entirety in the exercise of the general discretion in s 135 of the Evidence Act to exclude evidence. 109 Finally, the Full Court addressed a submission by the appellant that the matter should not be remitted to the primary judge. Before this Court, both parties made submissions about the effect of the Full Court's observations on this point (at 420-421 [112]-[114]) and it is convenient to set out those observations in full: [112] Cadbury says that it would be inappropriate for the proceeding to be remitted to the primary judge. Cadbury contends that, in the light of comments made by the primary judge in the course of ruling on the admissibility of the affidavits of Dr Gibbs, his Honour expressed views that indicated his Honour no longer has an open mind concerning the weight that should be accorded to the disputed evidence. Cadbury draws particular attention to the observation made by the primary judge that much of the factual material relied on by Dr Gibbs is vague, tendentious and of little weight. [113] However, in making those comments, his Honour was not referring to the opinions of Dr Gibbs but only to the factual material upon which his opinions were based. There is no reason to conclude that his Honour would not bring a fair and open mind to the question of specific objections to the disputed evidence and the resolution of the issues in the light of any part of the disputed evidence that might ultimately be admitted, consistently with these reasons. [114] In the circumstances, there is no reason why the proceeding should not be remitted to the primary judge for further hearing. Of course, if the primary judge were prepared to entertain a submission that he would not be able to bring an open mind to the resolution of the proceeding in the light of his Honour's earlier rulings both on the disputed evidence and in the final decision, it would be a matter for his Honour to decide whether he considered it was appropriate for the proceeding to be referred to another judge for a retrial ab initio. 110 The Full Court ordered that the appeal be allowed and that the matter be remitted to the primary judge for further hearing. 111 In its further reasons, the Full Court made the point that the matter had been remitted to the primary judge as though the case was part heard. The Court also said that it was for the primary judge to determine the extent to which additional or further evidence should be admitted. The Court made the point that it was possible that the disputed evidence might not be admitted into evidence, either because of proper objections taken to it, or because the primary judge might reject it in the exercise of the discretion in s 135 of the Evidence Act to exclude evidence. The Full Court said that there was no reason why the primary judge should entertain any contention that he should reverse earlier rulings made by him that were not in any way dependent upon the rejection of the evidence in issue, and that he should be in a position to conduct the further hearing as though he had admitted such of the disputed evidence as he found admissible after considering appropriate objections. The Court quoted its observations in [114] of the Court's earlier reasons and also said that it would be open to the primary judge to abort the trial if he concluded that admission of such of the disputed evidence as he was disposed to admit would cause injustice.

The further hearing before the primary judge 112 The appellant's submission on the disqualification application was that there was a case of apprehended bias in relation to the primary judge's decision as to the admissibility of the disputed evidence, the possible exclusion of the evidence under s 135 of the Evidence Act, the weight placed on the disputed evidence if admitted, and the findings to be made on the main issues in the appellant's application. 113 In his disqualification reasons, the primary judge referred at length to his evidence ruling and to the Full Court's reasons and further reasons. He also referred to an exchange between the Full Court and counsel for the respondent during the hearing of the appellant's application that the Court vary its previous order to provide that the matter be remitted to the primary judge for a new trial. The exchange which took place was as follows: Emmett J: … I think it is fair to say we use the word "further hearing", or the expression "further hearing", rather than a new trial, advisably. Mr Golvan: Yes, your Honour. Emmett J: But it is on the basis that the matter is now before the primary judge to do whatever his Honour would have done had he admitted that evidence in the first place. And if that involves reconsidering the exercise of discretion, then that would be a matter entirely for his Honour, but all of the evidence that there is there … Mr Golvan: That is so, your Honour. Emmett J: … unless, by chance, his Honour concluded that having regard to what has happened, he didn't think he could bring a fair mind to the matter. We have seen nothing in what he has said so far that that would indicate that. 114 The primary judge referred to the relevant test for apprehended bias, as laid down by the High Court in Johnson v Johnson (2000) 201 CLR 488 ("Johnson") (at 492 [11]): … whether a fair-minded lay observer might reasonably apprehend that the judge might not bring an impartial and unprejudiced mind to the resolution of the question the judge is required to decide.

(Citation omitted.) 115 The primary judge then referred to a particular submission made by the appellant concerning apprehended bias and the evidence of Ms Anne McGlinchey. As I have said, Ms McGlinchey was the respondent's marketing manager and she gave evidence as to how the respondent came to use the colour purple at Christmas in the years 2000-2004. She gave evidence that, in making the decision, she did not have an intention to associate the respondent with the appellant, or to copy the appellant. That evidence was relevant because, if such an intention had been established, that would have been strong evidence that the misleading of consumers had in fact occurred (see Australian Woollen Mills Ltd v FS Walton & Co Ltd (1937) 58 CLR 641 at 657). Ms McGlinchey was cross-examined by counsel for the appellant. The primary judge accepted her as a witness of truth. On the disqualification application, it was put to the primary judge by the appellant that the disputed evidence was relevant to Ms McGlinchey's evidence and that, as he had made a finding of credit concerning her evidence, a case of apprehended bias arose in relation to her evidence. The primary judge rejected that submission, saying that it was not explained to him how the disputed evidence might be put to a witness on issues going to the intentions and beliefs about the use of purple at Christmas 2000. The submission was repeated on the appeal and it is convenient to deal with it now. It was not explained to this Court how the disputed evidence might have been put to Ms McGlinchey on issues relevant to her intentions and beliefs about the use of purple at Christmas 2000 and, with respect, I think the primary judge was right to reject this particular submission of the appellant. 116 The primary judge then turned to consider the more general basis upon which the appellant put its case of apprehended bias. The primary judge said that the fair-minded lay observer would have regard, not only to his evidence ruling and substantive judgment, but also the Full Court's reasons, the exchange before the Full Court to which he had previously referred and the Full Court's further reasons. The primary judge said that the fair-minded lay observer would see that the Full Court saw no problem with the matter being further considered by him, and that the Court had not disapproved of observations made by the primary judge and judges in other cases on the utility of expert evidence in consumer cases. 117 The primary judge referred to the observations he made in his evidence ruling and said (at 791 [42]): The observer would see that, while there were critical comments on some aspects of Dr Gibbs' evidence, read as a whole and in context the real thrust of the remarks in the evidence ruling was concerned with the effects of expert evidence of this kind in this kind of case, in other words with the policy rationale for what the judge thought the law to be - wrongly, as it turned out. 118 The primary judge concluded his disqualification reasons with the following remarks (at 791 [43]): Of course there are practical problems. The reasonable lay observer would recognise the difficulty of a judge's task in taking into account new evidence when he or she has already reached a decision on a great deal of other evidence, including, although not limited to, evidence going to the same issues as the wrongly excluded evidence. But that is inherent in the power given by s 28(1)(c) of the Federal Court of Australia Act 1976 (Cth) which gives explicit powers to Full Courts to do what the Full Court has done in the present case.

Issues on the appeal 119 In my respectful opinion, the primary judge erred in not disqualifying himself from the further hearing of the proceeding. I have reached that conclusion having regard to all the circumstances, including what I regard as the most significant circumstance, namely, the remarks the primary judge made in the course of his evidence ruling which were specific to the evidence the appellant sought to adduce from Dr Gibbs. 120 The relevant test for apprehended bias is that set out in the reasons of the High Court in Johnson in the passage set out above ([114]). The High Court has referred to a number of principles which are relevant to the application of the test for apprehended bias. The cases, and the principles which emerge from them, are set out in the reasons for judgment of Greenwood J (at [70]-[74]). As the issue in this case is not the scope of the principles but their application to the facts of the case, it is not necessary for me to do other than provide a short summary of what I think are the more important principles, having regard to the circumstances of this case. 121 The test stated in Johnson refers to possibilities, not probabilities, although the possibilities must be real and not remote: Ebner v Official Trustee in Bankruptcy (2000) 205 CLR 337 at 345 [7] per Gleeson CJ, McHugh, Gummow and Hayne JJ. In circumstances in which it is alleged that a judge should disqualify himself or herself on the ground of a reasonable apprehension of bias by reason of prejudgment, the case must be firmly established and judges should not accede too readily to suggestions of appearance of bias: Re JRL; Ex parte CJL (1986) 161 CLR 342 ("Re JRL") at 352 per Mason J. It has also been said that a conclusion of a reasonable apprehension of bias is not to be drawn lightly: Vakauta v Kelly (1989) 167 CLR 568 at 584-585 per Toohey J. The fair-minded lay observer "is to be presumed to approach the matter on the basis that ordinarily a judge will so act as to ensure both the appearance and the substance of fairness and impartiality"; at the same time, he is "not presumed to reject the possibility of prejudgment or bias": Livesey v The New South Wales Bar Association (1983) 151 CLR 288 ("Livesey") at 299. 122 In Johnson, Gleeson CJ, Gaudron, McHugh, Gummow and Hayne JJ made observations on the need for any apprehension to be reasonable and on the knowledge to be attributed to the fair-minded lay observer. Their Honours said (at 493 [12]-[13]): … two things need to be remembered: the observer is taken to be reasonable; and the person being observed is "a professional judge whose training, tradition and oath or affirmation require [the judge] to discard the irrelevant, the immaterial and the prejudicial". Whilst the fictional observer, by reference to whom the test is formulated, is not to be assumed to have a detailed knowledge of the law, or of the character or ability of a particular judge, the reasonableness of any suggested apprehension of bias is to be considered in the context of ordinary judicial practice. The rules and conventions governing such practice are not frozen in time. They develop to take account of the exigencies of modern litigation. At the trial level, modern judges, responding to a need for more active case management, intervene in the conduct of cases to an extent that may surprise a person who came to court expecting a judge to remain, until the moment of pronouncement of judgment, as inscrutable as the Sphinx. In Vakauta v Kelly Brennan, Deane and Gaudron JJ, referring both to trial and appellate proceedings, spoke of "the dialogue between Bench and Bar which is so helpful in the identification of real issues and real problems in a particular case". Judges, at trial or appellate level, who, in exchanges with counsel, express tentative views which reflect a certain tendency of mind, are not on that account alone to be taken to indicate prejudgment. Judges are not expected to wait until the end of a case before they start thinking about the issues, or to sit mute while evidence is advanced and arguments are presented. On the contrary, they will often form tentative opinions on matters in issue, and counsel are usually assisted by hearing those opinions, and being given an opportunity to deal with them.

(Citations omitted.) (See also at 508-509 [53] per Kirby J.) (See also Concrete Pty Ltd v Parramatta Design & Developments Pty Ltd (2006) 229 CLR 577 at 609-610 [111] per Kirby and Crennan JJ.) 123 Apprehended bias may arise where a judge is required to make findings of fact about matters which were the subject of earlier findings of fact by the judge, which earlier findings have been set aside for whatever reason. The case of apprehended bias will be a strong one in cases in which the findings of fact turn on findings as to credit. It may be a strong one, even in those cases in which the findings of fact do not turn on findings of credit. Clearly, it depends on the precise circumstances of the case. In Livesey, the High Court said (at 300): It is, however, apparent that, in a case such as the present where it is not suggested that there is any overriding consideration of necessity, special circumstances or consent of the parties, a fair-minded observer might entertain a reasonable apprehension of bias by reason of prejudgment if a judge sits to hear a case at first instance after he has, in a previous case, expressed clear views either about a question of fact which constitutes a live and significant issue in the subsequent case or about the credit of a witness whose evidence is of significance on such a question of fact. On the other hand, in Re JRL, Mason J said (at 352): It needs to be said loudly and clearly that the ground of disqualification is a reasonable apprehension that the judicial officer will not decide the case impartially or without prejudice, rather than that he will decide the case adversely to one party. There may be many situations in which previous decisions of a judicial officer on issues of fact and law may generate an expectation that he is likely to decide issues in a particular case adversely to one of the parties. But this does not mean either that he will approach the issues in that case otherwise than with an impartial and unprejudiced mind in the sense in which that expression is used in the authorities or that his previous decisions provide an acceptable basis for inferring that there is a reasonable apprehension that he will approach the issues in this way. (See also Laws v Australian Broadcasting Tribunal (1990) 170 CLR 70 at 100 per Gaudron and McHugh JJ.) 124 The Court was referred to a decision of the Full Court of the Supreme Court of South Australia in Southern Equities Corp Ltd (in liq) v Bond (2000) 78 SASR 339 and a decision of the Court of Appeal of the Supreme Court of New South Wales in Baulkham Hills Shire Council v Basemount Pty Ltd (2003) 126 LGERA 339. The facts of this case differ from the facts in those two cases. While it has been helpful to look at those two authorities, this case is to be decided by the application of the general principles to the facts of the case. 125 The appellant did not put its submission of apprehended bias simply on the basis that, as a result of the decision of the Full Court, the primary judge was, or may have been, required to consider again factual matters about which he had previously made findings of fact (not based on findings of credit). That may be because of the nature of the error of the primary judge found by the Full Court and the fact that the Full Court said that, had the primary judge been right to exclude the disputed evidence, the appellant had not identified any error in his reasons. 126 The appellant's submission, or at least its primary submission, relied heavily on both certain statements and observations made by the primary judge in his evidence ruling and the fact that he was required to consider again matters about which he had previously made findings of fact. 127 In reaching the decision he did on the disqualification application, the primary judge appears to have placed significant weight on the observations of the Full Court in its reasons, on the exchange between the Court and counsel for the respondent previously referred to (at [113] above) in its further reasons and on the orders the Court made on the appeal. 128 The appellant submitted that the Full Court's observations at 420-421 [112]-[114] were directed to the issue of actual bias and not apprehended bias. The appellant submitted that, even if that was not the case, and the observations were directed to the issue of apprehended bias, the Full Court made it clear that, if an application for disqualification were made, it would be for the primary judge to determine the question of apprehended bias in accordance with the test in Johnson. The appellant submitted that the observations of the Full Court and the nature of the orders the Court made on the appeal were either irrelevant to any application to the primary judge for disqualification on the ground of apprehended bias, or together were only one factor in the determination of such an application. 129 The respondent did not contend that the Full Court had determined the question of apprehended bias on the material then before the Court. However, it did contend that the Full Court's observations were directed to the question of apprehended bias and that those observations and the orders the Court made on the appeal were relevant and significant matters which a fair-minded lay observer would take into account in deciding whether a reasonable apprehension of bias (within the test in Johnson) arose. 130 The words used by the Full Court in 420-421 [112]-[114] of its reasons suggest that the Court was directing its observations to the question of actual bias on the part of the primary judge. On the other hand, the respondent referred this Court to the submissions made to the Full Court by counsel for the appellant and the fact that, in the course of the submissions, counsel said that he was not suggesting actual bias on the part of the primary judge. It seems to me that at least two matters are clear. First, neither party suggested that the Full Court was dealing with possible apprehended bias on the part of the primary judge in a conclusive or authoritative way. In fact, it seems that the question of bias was not argued at any length before the Full Court. Secondly, even if the Full Court was addressing apprehended bias, the Court made it clear that it would be for the primary judge to determine any application for disqualification. In those circumstances, it is not clear to me that any weight should be placed on the Full Court's observations in the context of the application of the test involving the fair-minded lay observer. Of course, context is important and the fair-minded lay observer will always judge or assess the question in the particular context in which the question arises. The fair-minded lay observer is taken to know and understand a number of matters about how the legal system operates. Furthermore, and importantly, the apprehension of the fair-minded lay observer must be reasonable in the circumstances. Nevertheless, I have difficulty in seeing how, in the circumstances of this case, the observations of the Full Court, and the orders which the Full Court made, play any real part in the question of whether the primary judge should have disqualified himself. That question was to be determined by applying the test in Johnson. Even if I am wrong, and the Full Court's observations and the orders the Court made on the appeal are matters the fair-minded lay observer would take into account, I have nevertheless reached the conclusion, for the reasons which follow, that the primary judge erred in declining to disqualify himself. 131 In my opinion, a reasonable apprehension of bias arose in this case because of certain observations on Dr Gibbs' proposed evidence made by the primary judge in the course of his evidence ruling. In order to explain my reasons for this conclusion, it is necessary to examine the evidence ruling in detail. 132 The primary judge began by referring to the general rule in s 76 of the Evidence Act that evidence of an opinion is not admissible to prove the existence of a fact about the existence of which the opinion was expressed, and the exception to that rule in s 79. At the relevant time, s 79 was in the following terms: 79 Exception: opinions based on specialised knowledge If a person has specialised knowledge based on the person's training, study or experience, the opinion rule does not apply to evidence of an opinion of that person that is wholly or substantially based on that knowledge. 133 The primary judge referred to the fact that the respondent put an alternative submission that he should exercise the discretion contained in s 135 of the Evidence Act to exclude the evidence. That section provides: 135 General discretion to exclude evidence The court may refuse to admit evidence if its probative value is substantially outweighed by the danger that the evidence might: (a) be unfairly prejudicial to a party; or (b) be misleading or confusing; or (c) cause or result in undue waste of time. 134 The primary judge summarised Dr Gibbs' evidence. He said that he accepted that marketing and behavioural science was an organised and recognised area of specialised knowledge and that Dr Gibbs had training, study and experience within that area. However, he said that the evidence was not admissible because Dr Gibbs' opinions were not outside the knowledge or experience of ordinary persons. As the Full Court said, in reaching that conclusion he, and indeed counsel appearing before him, overlooked s 80(b) of the Evidence Act. 135 The primary judge went on to refer to observations by judges in other cases and the author of a well-known text on the limited utility of, and sometimes dangers associated with, expert evidence in consumer cases. The primary judge then said (at 725 [23]-[24]): 23. Senior counsel for Cadbury referred to the assistance he said I could receive from Dr Gibbs' evidence and how it could be helpful. Without wishing to seem ungrateful, or disrespectful to Dr Gibbs, I think the evidence would not be helpful at all. Rather, it would create many areas of disputation with opposing experts and greatly complicate and lengthen the trial of this proceeding. The observations of Branson J in Cat Media are very much in point. 24. I rule that the affidavits of Dr Gibbs are not admissible. ... 136 I would be disposed to think that if the evidence ruling stopped at this point, a case of apprehended bias, having regard to what the primary judge said and the other circumstances of the case, would not be made out. The primary judge had ruled on a point of evidence and, although he had made observations to that point on the utility of the type of evidence Dr Gibbs was proposing to give, those observations were of a general nature and were not so strongly expressed as to suggest to the fair-minded lay observer that he might not have an open mind as far as Dr Gibbs' evidence and the issues that flowed from its possible admission were concerned. 137 The primary judge went on to consider whether he would have excluded Dr Gibbs' evidence under s 135 of the Evidence Act, assuming it was otherwise admissible. He addressed the probative value of Dr Gibbs' evidence and weighed it against the danger that the evidence might cause or result in undue waste of time. 138 In addressing the probative value of Dr Gibbs' evidence, the primary judge said that much of the factual material relied on by Dr Gibbs "is not in evidence, or likely to be in evidence, or is vague, tendentious and of little weight". The factual material relied on by Dr Gibbs, which was not in evidence, was the market research reports by persons who were not to be called as witnesses, and the vague and self-serving statements were contained in material provided to Dr Gibbs by the appellant's solicitors. As I understood it, the respondent submitted that the fair-minded lay observer would understand that these comments by the primary judge were directed, not to Dr Gibbs' opinions, but, rather, to the material upon which they were based. It seems to me that the answer to this submission is that to attribute such an understanding to the fair-minded lay observer is to attribute to him or her a degree of perception which is not warranted. In any event, it seems to me that, however one looks at it, the comments made by the primary judge are comments about Dr Gibbs' proposed evidence and bear on the issue of the weight it was likely to be given. 139 The primary judge then referred to Dr Gibbs' proposed evidence about the similarity between the appellant's colour purple and the respondent's colour purple. He referred to evidence Dr Gibbs proposed to give about research from a "sensation/perception psychologist's website" to the effect that whilst about 150 hues could be discriminated across the colour spectrum in side-by-side comparison, only about 17 were discernible in colour memory. The primary judge said that Dr Gibbs' evidence on this point seemed to amount to "part speculation and part unnecessary intellectualisation of a simple question of consumer product comparison" and that "[t]he potential for time wasting cross-examination is obvious". It is true that these observations were made in the context of the possible exercise of the discretion in s 135 of the Evidence Act and whether there was a danger that the evidence might cause or result in undue waste of time, but, nevertheless, they are observations on Dr Gibbs' proposed evidence and they bear on the issue of the weight it was likely to be given. 140 Towards the end of his reasons, the primary judge identified what he referred to as some important policy considerations, although he made it clear that he did not suggest that they were within the specific discretionary factors within s 135. 141 Although a reference to general policy considerations may not of itself create difficulty in terms of apprehended bias, the difficulty here is that the primary judge identified the admissibility of Dr Gibbs' evidence with those policy considerations. He said (at 726 [31]): The law on s 52 and passing off is well settled. Factual issues which arise in the context of widely marketed consumer goods and services are often straightforward. The present case is a good example. If it becomes accepted that the only way to conduct these cases is by the calling of evidence like that of Dr Gibbs, solicitors will feel they have to advise such a course for fear of being sued for negligence if they do not. Large companies will be in a position to hold out the threat of ruinous costs over smaller competitors ("emboldened competitors" as Dr Gibbs would have it). Competition will be stifled. The delicate balance between the laws of fair trading and the laws of competition will be distorted.

(Emphasis added.) 142 The respondent submitted that the proper characterisation of the primary judge's evidence ruling is that it was a ruling about a point of evidence which turned largely on a matter of law and that the primary judge's views about Dr Gibbs' evidence were no more than tentative or provisional views. The respondent pointed to the fact that the primary judge had not heard Dr Gibbs' evidence and that he made no findings about Dr Gibbs' principal conclusions. There is no doubt the primary judge did rule on a point of evidence and that, as far as admissibility is concerned, his ruling turned on a point of law. Clearly, he did not hear the evidence of Dr Gibbs. However, in considering the probative value of the evidence for the purposes of making a ruling under s 135 of the Evidence Act, the primary judge made strong comments about Dr Gibbs' evidence and the weight it was likely to be given. Those comments were not tentative or provisional. It seems to me that to characterise the occasion upon which the observations or comments said to give rise to apprehended bias were made can be of assistance, but that it cannot be allowed to obscure the essential question in the Johnson test. 143 The respondent also submitted that the fair-minded lay observer would take into account the fact that further evidence could be called on the application to tender the disputed evidence and that the primary judge had allocated a substantial period of time for the further hearing of the proceeding. They are matters to be taken into account, but they do not outweigh the considerations supporting the conclusion that the primary judge should have disqualified himself. 144 In my respectful opinion, those comments or observations of the primary judge which were specifically directed to the evidence proposed to be adduced from Dr Gibbs were such that a fair-minded lay observer might reasonably apprehend that the primary judge might not bring an impartial and unprejudiced mind to the resolution of the questions the primary judge was required to decide on the further hearing. The primary judge erred in declining to disqualify himself.

Conclusion 145 The appellant has made out grounds one and two of the appeal and the appeal must be allowed. In view of the conclusion reached by the other members of the Court, it is not necessary for me to consider further the orders which should be made in light of my conclusions.

I certify that the preceding fifty-six (56) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Besanko.

Counsel for the Appellant: Mr N Hutley SC with Mr M D Wyles and Mr S Rebikoff

Solicitor for the Appellant: Mallesons Stephen Jaques

Counsel for the Respondent: Mr C Golvan SC with Dr Ricketson