Workers' compensation - Determination of level of disability - Construction of Form 22 and reg 19J of the Workers' Compensation and Rehabilitation Regulations 1982 - Whether Western Power Corporation v McMullen [2004] WASCA 3 should be overruled - Principles regarding departure from earlier decision of same court

Interpretation Act 1984 (WA), s 21, s 37(1), s 41(1)

Workers' Compensation and Rehabilitation Act 1981 (WA), s 18, s 22, s 84ZN(2), s 93B, s 93D, s 93E

Workers' Compensation and Rehabilitation Amendment Regulations (No 11) 1999 (WA)

Workers' Compensation and Rehabilitation Regulations 1982 (WA), reg 19J, reg 19N

Austal Ships Pty Ltd v Sen [2004] WASCA 224

Brayson Motors Pty Ltd (in liq) v Federal Commissioner of Taxation [1985] HCA 20; (1985) 156 CLR 651

Deputy Federal Commissioner of Taxation for South Australia v Ellis & Clark Ltd [1934] HCA 54; (1934) 52 CLR 85

Elazac Pty Ltd v Commissioner of Patents [1994] FCA 1315; (1994) 53 FCR 86

Esso Australia Resources Ltd v Commissioner of Taxation of the Commonwealth of Australia [1999] HCA 67; (1999) 201 CLR 49

Hunter Resources Ltd v Melville [1988] HCA 5; (1988) 164 CLR 234

John v Federal Commissioner of Taxation [1989] HCA 5; (1989) 166 CLR 417

Kavanagh v Claudius (1907) 9 WALR 55

Neill v Glacier Metal Co Ltd [1965] 1 QB 16

Nguyen v Nguyen [1990] HCA 9; (1990) 169 CLR 245

Queensland v The Commonwealth [1977] HCA 60; (1977) 139 CLR 585

Re Calder; Ex parte Cable Sands (WA) Pty Ltd (1998) 20 WAR 343

Re Monger; Ex parte Ivey [1999] WASC 250

The Commonwealth of Australia v Hospital Contribution Fund of Australia [1982] HCA 13; (1982) 150 CLR 49

Tzaidas v Child [2004] NSWCA 252; (2004) 61 NSWLR 18

Ward v Commissioner of Police (1998) 151 ALR 604

Webster v McIntosh [1980] FCA 128; (1980) 32 ALR 603

Western Power Corporation v McMullen [2004] WASCA 3

Alcoa of Australia Ltd v Ferraro, unreported; CM­134/00; 1 December 2000; 1111 (Magistrate Cockram)

Coles Myer v Janissen, unreported; CM­26/95; 26 April 1995; 786 (Magistrate Cockram)

Farmer v AOC Australia Pty Ltd [2002] WASCA 340

Girrawheen Tavern v Joseph [2003] WASCA 244

In re Flavel (decd) [1916] SALR 47

Kuligowski v Metrobus [2002] WASCA 170; (2002) 26 WAR 137

R v Toohey; Ex parte Northern Land Council [1981] HCA 74; (1981) 151 CLR 170

Rasmussen v Kilpatrick Green Holdings Ltd, unreported; CM­97/00; 23 January 2001; 1120 (Magistrate Cockram)

Re Butler; Ex parte Toohey's Ltd (1934) 34 SR (NSW) 277

Re Monger; Ex parte Cook's Construction Pty Ltd [2004] WASCA 165

Re Monger; Ex parte Cross [2004] WASCA 176

Re Monger; Ex parte Dutch [2001] WASCA 220; (2001) 25 WAR 96

Re Monger; Ex parte Velsberry Pty Ltd [2003] WASCA 9

Re Monger; Ex parte Wilderness Equipment Pty Ltd [2003] WASCA 202

The Mayor, Councillors and Citizens of the City of Brunswick v Stewart [1941] HCA 7; (1941) 65 CLR 88

Tion v WA Meat Marketing Co International Ltd, unreported; CM­49/02; 16 October 2002; 1263 (Magistrate Hogan)

Tomlinson v Bullock (1879) 4 QBD 230

Transfield Pty Ltd v Rawstron [2005] WASCA 78

1 JUDGMENT OF THE COURT: This is an appeal against the decision of a Compensation Magistrate given in respect of a dispute arising under the terms of the former Workers' Compensation and Rehabilitation Act 1981 (WA) ("Act"). The appeal challenges the prior decision of the Full Court of this Court in Western Power Corporation v McMullen [2004] WASCA 3. Consequently, a bench of five has been convened to hear it.

2 In order to understand the issues arising in the appeal, it is necessary to set out the relevant structure of the Act as it stood at the material time.

3 By s 18, if a disability of a worker occurs, the worker's employer is, subject to the Act, liable to pay compensation to the worker in accordance with Sch 1 thereof.

4 Division 2 of the Act imposes constraints on awards of common law damages. These constraints apply, by section 93B, in the case of a worker whose disability was caused by the negligence or other tort of the worker's employer and to whom compensation has been paid or is payable under the Act in respect of the disability, or to whom it would have been paid or payable but for s 22 thereof (which deals with serious and wilful misconduct). The principal provision imposing the constraints is s 93E(3) which provides that:

(a) it is agreed or determined that the degree of disability is not less than 30% and that agreement or determination is recorded in accordance with the regulations; or

(b) the worker has a significant disability [s 93E(4) provides that the worker will have a significant disability if it is agreed or determined that the degree of disability is not less than 16% and that agreement or determination is recorded in accordance with the regulations] and elects, in the prescribed manner, to retain the right to seek damages and the election is registered in accordance with the regulations."

5 The significance of the distinction between the two levels of disability appears from s 93E(8). That section provides that, subject to other provisions which are not presently relevant, if an election has been made under subs (3)(b), compensation under the Act is not payable in respect of the disability in relation to any period after the day on which the election is registered. Subsection (9) provides that subs (8) ceases to apply if, after the election is made, it is agreed or determined that the degree of disability is 30 per cent or more and that agreement or determination is recorded in accordance with the regulations.

6 Section 93D prescribes the manner in which a worker's degree of disability is to be assessed. It also provides what is to happen in the event of disagreement between the worker and the employer. Section 93D(5) provides, in this respect, that:

"If the worker and the employer cannot agree on whether the degree of disability is not less than the relevant level, the worker may, subject to subsection (6) refer the question to the Director."

7 The words "relevant level" are defined by s 93D(1) to mean:

"(a) if the question arises for the purposes of section 93E(3)(a), (9) or (12), a degree of disability of 30%; or

(b) if the question arises for the purposes of section 93E(4), a degree of disability of 16%."

8 Sections 93D(6) to (10) and (12) read as follows:

"(6) A question can only be referred under subsection (5) if the worker produces to the Director medical evidence from a medical practitioner indicating that, in the medical practitioner's opinion, the degree of disability is not less than the relevant level.

(7) As soon as practicable after receiving a referral under subsection (5) the Director is to notify the employer in accordance with the regulations.

(8) If within 21 days after being notified under subsection (7) the employer notifies the Director in accordance with the regulations that the employer considers that the degree of disability is less than the relevant level, a dispute arises for the purposes of Part IIIA.

(9) The Director is to consider the dispute in consultation with the parties.

(10) Except in a case to which subsection (11) applies [that subsection is not presently relevant], if the dispute is not resolved by agreement the Director is to refer the question for resolution under the provisions of Part IIIA [which deals with dispute resolution, inter alia, by review officers] ... .

(11) ...

(12) Unless notification is given by the employer under subsection (8), the employer is to be regarded as having agreed that the degree of disability is not less than the relevant level."

9 Until 14 December 1999 reg 19J of the Workers' Compensation and Rehabilitation Regulations 1982 (WA) ("Regulations") provided only, so far as is relevant, that a referral under s 93D(5) of the Act was to be made in the form of Form 22 in Appendix 1 of the Regulations. That form ("original form") made provision for the filling in of details relating to the worker, the employer and the worker's injury. It also made provision for a statement of the degree of disability as assessed by a medical practitioner. Finally, it contained two boxes under the heading "Relevant level of disability (see s 93E(3) of the Act)". The first box was to be ticked if the worker asserted a level of disability of "not less than 30%". The second was to be ticked if the worker asserted a level of disability of "not less than 16%".

The amendment of reg 19J and the cases of Ivey and McMullen

10 On 10 December 1999 Re Monger; Ex parte Ivey [1999] WASC 250 was decided. It concerned the return, before a single Judge of the Supreme Court, Miller J, of an order nisi for a writ of mandamus. A worker who had suffered a disability lodged a Form 22 referral with the Director pursuant to s 93D(5) of the Act. In it, she had ticked the box asserting that the relevant level of disability was not less than 30 per cent. The Director did not accept that that level of disability was supported by the medical evidence provided by the worker pursuant to s 93D(6). He consequently refused to accept the referral. Miller J found that it was open to the Director to reach the conclusion at which he had arrived in respect of the degree of disability established by the medical evidence. However, he said that this did not justify rejection of the referral if the medical evidence revealed a level of disability of not less than 16 per cent. He went on to say:

"It cannot be the case that if the applicant simply ticks the 'not less than 30%' box on the Form 22 he or she is precluded from the benefit of the provisions of s 93D(7) et seq where the medical practitioner's report fails to indicate a relevant level of not less than 30 per cent but nevertheless reveals a relevant level of not less than 16 per cent. If it were the case that a worker was to be bound by an election in the Form 22, s 93D(6) could easily have provided that the medical practitioner's opinion must indicate a degree of disability of not less than one of, and only one of, the relevant level. Likewise, reg 19J (which I consider to be within power by reason of the general regulation-making power contained within s 176(1)(a) of the Act) could have required a referral made in the form of Form 22 in Appendix 1 to nominate one, and only one, relevant level of disability being claimed. The form itself could also have required the worker to nominate one and only one relevant level, indicating that the level elected for would be limiting and binding."

11 Four days later, on 14 December 1999, reg 19J and Form 22 of the Regulations were amended by the Workers' Compensation and Rehabilitation Amendment Regulations (No 11) 1999 (WA) ("1999 amendments"). The amended reg 19J(1) reads as follows:

"(1) Subject to regulations 19JA and 19JB [which are not presently material], a referral under section 93D(5) of the Act -

(a) is to be made in the form of Form 22 in Appendix 1; and

(b) is to nominate in the Form 22 one, and only one, relevant level of disability in respect of which the referral is made."

12 The amended Form 22, under the heading "Relevant level of disability (see s 93E(3) of the Act)", had the same two boxes with the same two notations with respect to the relevant level of disability as had appeared on the original form, but now carried a requirement that "only one relevant level of disability" was to be nominated.

13 In January 2004, McMullen was decided. In that case the worker had used the amended Form 22 to make a referral to the Director. He nominated a relevant level of disability of not less than 30 per cent. The review officer determined that the worker's degree of disability was between 16 per cent and 29 per cent. The appellant contended that he should not have done so and that the question which was referred to the Director was confined to that of whether or not the worker had sustained a disability of the level nominated by him. Wallwork AJ, with whom the other members of the Court (Malcolm CJ and Miller J) agreed, upheld that contention. After mentioning that the amendments to the Regulations appeared to be taken from Miller J's reasons for judgment in Ivey, Wallwork AJ went on to say that the Regulations were part of an "overall statutory scheme" and that they had been amended "to supply additional information to assist the scheme and to cure the difficulties which had been referred to by Miller J in Ivey". He said that there had been no need to amend the Act.

14 In this case the injured worker lodged a Form 22 referral with the Director on 14 December 1999, before the publication in the Government Gazette, later that day, of the 1999 amendments. He used the original form and nominated a level of disability of not less than 30 per cent. The respondent, who was the worker's employer, was given the requisite notice under s 93E(8) of the Act. It notified the Director (by means of a response in the form provided for by Form 23 of the Regulations) that its assessment of the worker's level of disability was "nil%". A dispute consequently arose and, because it was not resolved by agreement, the Director referred it for resolution by a review officer under the provisions of Pt IIIA of the Act. The review officer determined that the worker's level of disability was not less than 16 per cent.

The decision of the Compensation Magistrate

15 The respondent appealed to a Compensation Magistrate under the provisions of s 84ZN(2) of the Act, asserting that the review officer had lacked the jurisdiction to find that the worker's level of disability was not less than 16 per cent when the question referred to him was that of whether the respondent's level of disability was not less than 30 per cent. By the time the appeal was heard, McMullen had been decided (it had not been decided at the time of the review officer's decision). The Compensation Magistrate said that he was bound to apply that case. However, the worker's counsel submitted that, because the worker had lodged his Form 22 referral before publication of the 1999 amendments in the Government Gazette, the amendments did not apply to him and his claim was governed by the law as it had stood at the time of Ivey.

16 This submission raised for consideration the provisions of ss 21, 37(1) and 41(1) of the Interpretation Act 1984 (WA). Sections 21 and 41(1) of that Act read as follows:

"21. Time of commencement of written laws

Where any written law, or portion of a written law, comes into operation on a particular day, it shall come into operation at the beginning of that day.

41. Publication and commencement of subsidiary legislation

(1) Where a written law confers power to make subsidiary legislation, all subsidiary legislation made under that power shall -

(a) be published in the Gazette;

(b) subject to section 42, come into operation on the day of publication, or where another day is specified or provided for in the subsidiary legislation, on that day."

17 Section 37(1) of the Interpretation Act provides (relevantly) that:

"Where a written law repeals an enactment, the repeal does not, unless the contrary intention appears -

(a) ...

(b) affect the previous operation of the enactment repealed or anything duly done or suffered under that enactment;

(c) affect any right, interest, title, power or privilege created, acquired, accrued, established or exercisable or any status or capacity existing prior to the repeal;

...

(f) affect any investigation, legal proceeding or remedy in respect of any such right, interest, title, power, privilege, status, capacity, duty, obligation, liability, burden of proof, penalty or forfeiture,

and any such investigation, legal proceedings or remedy may be instituted, continued, or enforced, and any such penalty or forfeiture may be imposed and enforced as if the repealing written law had not been passed or made."

18 Counsel for the worker argued that, if McMullen was to be applied to the worker's referral, this would have the effect that the amended reg 19J would operate retrospectively (by a matter of hours) contrary to the provisions of s 37(1)(b) to which, he said, s 21 was subject, when that had not been provided for in the Regulations.

19 The Magistrate rejected this argument. He said that there was no inconsistency between the relevant provisions of the Interpretation Act and that, "to the extent that ... [s 21 of that Act] winds back the clock to the beginning of the day in question ... [it] must ... be viewed as specifically legislating for a retrospective effect for every written law expressed to come into operation on a particular day". He consequently allowed the appeal.

20 In his appeal against the decision of the Compensation Magistrate, brought in this Court, the worker raises two grounds, as follows:

"A. The learned Magistrate erred in law in concluding that Section 21 of the Interpretation Act applied to the exclusion of Section 37 of the Interpretation Act, and/or that the latter ought to be read as being subject to the former.

B. The learned Magistrate at Reasons [28] erred in law in misapplying the decision in Western Power Corporation v McMullen [2004] WASCA 3 (hereafter, 'McMullen'). Alternatively McMullen was wrongly decided and ought to be overruled.

Particulars

(a) the Reasons of his Honour Wallwork J in McMullen at [42] wrongly describe the question referred in the Form 23 as being the basis of the Review Officer's 'jurisdiction', when in fact it is s.93D of the Act which gives a Review Officer jurisdiction to determine a worker's 'relevant level' as defined in the Act and explained in Re Monger; ex parte Ivey at [17], [22]. Alternatively, the parameters of the actual 'dispute' referred to the Review Officer as per the completed Form 23 was that the worker's degree of disability was somewhere between '0%' and '30%';

(b) contrary to McMullen at [41], the Regulations made never passed Parliament as part of the 'overall statutory scheme' and should not be used in the process of ascertaining legislative intention."

21 The respondent has lodged a notice of contention, the particulars of which read as follows:

"1. In fact, the appellant's referral pursuant to s.93D(5) of the Workers' Compensation & Injury Management Act 1981 only referred the question whether the appellant's relevant level of disability was not less than 30%.

2. Further, in law, the appellant's referral could only refer the question whether the appellant's degree of disability was not less than 30%, that being the question on which the appellant and the respondent could not agree.

3. The jurisdiction of a review officer to determine the appellant's referral made pursuant to s.93D(5) was limited, by reason of Division 3 of Part IIIA and ss.93D(10), 104A(1), to the question which was the subject of the referral."

22 We propose to deal, first, with the issue raised by ground B of the grounds of appeal and by the notice of contention ("referral issue"), before returning to the issue raised by ground A ("retrospectivity issues").

23 As will be apparent, the referral issue involves a challenge to the correctness of what was decided in McMullen.

24 This Court, consisting of five members, is entitled to decide whether it will or will not follow the decision arrived at in McMullen, that being a decision arrived at by three Judges: Re Calder; Ex parte Cable Sands (WA) Pty Ltd (1998) 20 WAR 343 per Steytler J at 354, Kennedy, Pidgeon, White and Wheeler JJ agreeing; Kavanagh v Claudius (1907) 9 WALR 55 at 58, per Parker CJ. Indeed, a court consisting of three members may overrule an earlier decision of its own or of the Full Court in an appropriate case.

25 However, this Court will not lightly depart from one of its previous decisions or from a previous decision of the Full Court, particularly when that decision has been applied by another Full Court or a differently constituted Court of Appeal. This Court would only do so in circumstances in which it is convinced that the earlier decision was wrong or when there is some other compelling reason why the previous decision should no longer be followed: Calder at 354. In Nguyen v Nguyen [1990] HCA 9; (1990) 169 CLR 245 at 269, Dawson, Toohey and McHugh JJ said that a court of appeal, although free to depart from an earlier decision, should do so "cautiously". It is nonetheless a Judge's duty to apply the law as he or she understands it after careful consideration and with keen appreciation of the importance of certainty in the law and equal appreciation that adherence to a decision thought to be wrong can cause injustice: Tzaidas v Child [2004] NSWCA 252; (2004) 61 NSWLR 18 at 28. In John v Federal Commissioner of Taxation [1989] HCA 5; (1989) 166 CLR 417 at 438 - 439, Mason CJ, Wilson, Dawson, Toohey and Gaudron JJ said that there is no definite rule as to the circumstances in which the High Court will reconsider an earlier decision, but then referred to four matters or considerations which had been identified in The Commonwealth of Australia v Hospital Contribution Fund of Australia [1982] HCA 13; (1982) 150 CLR 49 as justifying departure from earlier decisions. The first was that the earlier decisions did not rest upon a principle carefully worked out in a significant succession of cases. The second was a difference between the reasons of the Justices constituting the majority in one of the earlier decisions. The third was that the earlier decisions had achieved no useful result, but on the contrary had led to considerable inconvenience and the fourth was that the earlier decisions had not been independently acted on in a manner which militated against reconsideration. The fourth matter has led some Judges to follow a decision they considered to be wrong because the earlier decision had been acted upon: see Queensland v The Commonwealth [1977] HCA 60; (1977) 139 CLR 585 per Gibbs and Stephen JJ. Hospital Contribution Fund has been applied recently in Esso Australia Resources Ltd v Commissioner of Taxation of the Commonwealth of Australia [1999] HCA 67; (1999) 201 CLR 49 (cf however, the additional comments made by Callinan J at [164]).

26 In our opinion the four considerations mentioned in Hospital Contribution Fund are also relevant when intermediate courts are deciding whether or not to overrule an earlier decision.

27 McMullen is not a decision which rests upon a principle carefully worked out in a significant succession of cases. We were referred to only one case in which it has been applied. That was the decision of the Full Court, given ex tempore, in Austal Ships Pty Ltd v Sen [2004] WASCA 224. However, in that case, the respondent had lodged two referrals, one in which he nominated a level of disability of not less than 16 per cent and another in which he nominated a level of disability of not less than 30 per cent. He thereafter withdrew the first of his referrals, leaving only the second for determination, and thereby disclaimed any reliance upon the lesser level. Moreover, there was in that case no challenge to the correctness of McMullen.

28 The second consideration mentioned in the Hospital Contribution Fund case is not applicable here. As to the third, the decision in McMullen has achieved no useful result. The Court was told that the usual practice now is for workers to lodge two referrals, one of which has a "not less than 16%" box ticked and the other being an identical form based on the same medical evidence, in which the "not less than 30%" box is ticked. That cannot be said to give rise to "considerable inconvenience" but it is a rather pointless, and questionable, outcome. As to the fourth consideration, while McMullen was applied in Austal, that was done in the circumstances to which we have referred which, in our opinion, do not militate against reconsideration.

29 As Callinan J has said in Esso, the applicability of one or more of these considerations does not mandate departure from the earlier decision. It is still necessary to consider whether or not the decision is wrong. The appellant argues that McMullen is wrong. His argument, reduced to its essence, is that, while reg 19J obliges the worker making a referral under s 93D(5) of the Act to nominate in Form 22 "one, and only one, relevant level of disability", this does not preclude the Review Officer from making a determination, in a case in which the "not less than 30%" box has been ticked, that the relevant level is in fact between 16 per cent and 30 per cent if that is revealed by the evidence.

30 The question is one of statutory construction. That requires attention to the words of the Act, which govern what may be done in the regulations. It is a general rule of statutory construction that the intention of Parliament, in enacting an Act, is not to be ascertained by reference to the terms in which a delegated power to legislate has been exercised: Webster v McIntosh [1980] FCA 128; (1980) 32 ALR 603 at 606, per Brennan J, with whom Deane and Kelly JJ agreed; Hunter Resources Ltd v Melville [1988] HCA 5; (1988) 164 CLR 234 at 244, per Mason CJ and Gaudron J.

31 There are, of course, exceptions to the general rule.

32 One of these is that, if the regulations and the principal Act form part of a legislative scheme, the regulations may be referred to in order to ascertain the nature of the scheme: Deputy Federal Commissioner of Taxation for South Australia v Ellis & Clark Ltd [1934] HCA 54; (1934) 52 CLR 85 at 89 - 95; and Brayson Motors Pty Ltd (in liq) v Federal Commissioner of Taxation [1985] HCA 20; (1985) 156 CLR 651 at 652 (where, in the course of discussion with counsel, recorded in the report, Mason J said that regulations are looked at, not to constitute an overall scheme or to throw light on ambiguity in a statutory provision, but to ascertain what the scheme is) and see, generally, Pearce & Geddes: Statutory Interpretation in Australia, 5th ed, at [3.37]. In this instance, of course, we are concerned with an amendment to the Regulations made after the material provisions of the Act came into operation.

33 A second exception may be open, enabling delegated legislation to be referred to as an aid in construing an ambiguous statutory provision, where the Act and regulations are contemporaneously prepared and establish an interdependent scheme: Elazac Pty Ltd v Commissioner of Patents [1994] FCA 1315; (1994) 53 FCR 86 at 89 - 91, per Heerey J, and Neill v Glacier Metal Co Ltd [1965] 1 QB 16 at 27, per Sachs J. Again, this can have no application in the case of a regulation amended after, and independently of, the enactment of the material provisions of the Act.

34 A third exception has been suggested by Moore J in Ward v Commissioner of Police (1998) 151 ALR 604 at 614, to the effect that, if a statutory provision permits exceptions to be made to it by regulations, the regulations might be referred to as an aid to the interpretation of the provision. Also (although this is not strictly a matter of statutory construction), it may be that, where the effect of a provision is that it is to operate in accordance with the regulations as they exist from time to time, the manner of the operation of that provision will be governed by the regulations.

35 In this case, as will be apparent from what we have earlier said, the essence of the statutory scheme is as follows, so far as the imposition of constraints on awards of common law damages is concerned. Where the degree of disability is less than 16 per cent, a worker is confined to workers' compensation payments. Where the degree of disability is more than 16 per cent, but less than 30 per cent, the worker must elect whether or not to retain the right to seek common law damages. If the worker does so, workers' compensation ceases to be payable. Where the degree of disability is more than 30 per cent, the worker can seek common law damages while retaining the right to receive workers' compensation payments (although the amount of the workers' compensation payments will be deducted from any award of common law damages).

36 We have earlier said that s 93D stipulates the procedure for determining what is the worker's degree of disability. The principal mechanism should be one of agreement between the worker and the employer: s 93D(5). However, where the two cannot agree, if the worker is able to produce an opinion from a medical practitioner that his or her degree of disability is not less than the relevant level (either 16 per cent or 30 per cent) he or she may, by means of a Form 22, "refer the question" to the Director: ss 93D(5) and (6). The Director then notifies the employer (by forwarding on to the employer a document in accordance with Form 23) and the employer must, within 21 days, notify the Director whether or not it considers the degree of disability to be "less than the relevant level": s 93D(7) and (8) and reg 19J(2). It does so by specifying, on the Form 23, its assessment of the degree of disability (reg 19J(3)) and returning that form to the Director. If the employer considers that the degree of disability is "less than the relevant level", a dispute arises. The Director then considers the dispute in consultation with the parties and (so far as is relevant for present purposes), if the dispute is not resolved by agreement, the Director refers "the question" for resolution by a review officer (ss 93D(8), (9) and (10)).

37 It is plain from this legislative structure that, where the worker nominates a degree of disability of 16 per cent or more, but less than 30 per cent, and the employer nominates one of less than 16 per cent; or where the worker nominates a degree of disability of 30 per cent or more, but the employer nominates one of 16 per cent or more but less than 30 per cent, only one question is capable of arising for resolution by the review officer. In the former case it will only be whether the level of disability is 16 per cent or more. In the latter case it will be whether the level is 30 per cent or more because the parties agree that the level of disability is at least 16 per cent or more and will require a determination only about whether the degree of disability is 30 per cent or more. In this last instance it will be open to the worker to make an election under s 93E(3)(b) and if, having done so, it is later determined that the level of disability is 30 per cent or more, that determination can be recorded in accordance with the Regulations and s 93E(8) will cease to apply. The only occasion upon which the question of construction posed in this case will arise is in a case such as the present, where the worker nominates a degree of disability of 30 per cent or more and the employer nominates one of less than 16 per cent.

38 Leaving to one side, for the moment, what was said in Ivey and in McMullen, it seems to us that the question which is referred to the Director under s 93D(5) and, where necessary, by the Director to the review officer under s 93D(10), is that of what is the degree of disability suffered by the worker. While s 93D(5) speaks of the question "whether the degree of disability is not less than the relevant level", there will, in many cases, be only one relevant level in contention, as we have explained. The question, then, will be whether the degree of disability reaches that level. Where the ambit of the dispute ranges (as in this case) between somewhere less than 16 per cent (the insurer's nomination) and 30 per cent or more (the worker's nomination) there will be two relevant levels in contention, unless the worker has made it plain that he or she will elect not to rely upon the lower level. However, even then, only one relevant level can be determined (or agreed upon, if agreement is reached after consultation with the Director), being either of 16 per cent or more or 30 per cent or more. Consequently, the question which is referred by the Director for resolution is always the same, being that of what is the relevant level or, to put it differently, what is the degree of disability. When the operation of the Act is understood in that way, it is not surprising that the original Form 22 should have had the two boxes to which I have referred. In our opinion, where the amended Form 22 requires the worker to tick only one of the two boxes, that tick and the employer's nomination do no more than delineate the ambit of the dispute. The regulatory requirement that the worker is to tick only one box has no effect on the task which the Act requires, which is the determination of the degree of disability.

39 That the construction which we have preferred was that intended by the legislature seems to us to be supported by one consequence of the construction contended for on behalf of the respondent. Section 93E(5) provides that, subject to subss (6) and (7), if weekly payments of compensation in respect of the disability have commenced, an election cannot be made under subs (3)(b) after the "termination day", being the day that is six months after the day on which weekly payments commenced: s 93E(1). Subsection (6) extends the time within which an election can be made but not, on the respondent's construction of the Act, in a case such as the present (it applies only where the question referred to the Director is that of "whether the degree of disability is not less than 16%"). Subsection (7) empowers the Director, in circumstances set out in the Regulations, to extend the period within which an election can be made under subs (3)(b). However, the circumstances provided for in the Regulations are very limited: see reg 19N. Moreover, the extension can be granted only until a day that is not more than six months after the termination day. As counsel for the respondent acknowledged, there is consequently a very real prospect that, on the construction of the Act advanced by him, a worker who nominates a level of disability of more than 30 per cent, but who fails to achieve a determination accordingly, will have insufficient time, thereafter, to prove a disability of not less than 16 per cent so as to make an election under subs 3(b) before the termination day, or even an extended termination day. We very much doubt that that could have been intended by the legislature.

40 That brings us back to Ivey and McMullen.

41 As to Ivey, it seems to us, with due respect, to be plain from s 93D(6) that, whatever level is nominated by the worker, that level must be supported by a medical practitioner's opinion before the question can be referred to the Director under subs (5). Consequently, a Form 22 which nominated a level of 30 per cent or more, but which was supported by a medical opinion nominating a level of less than 30 per cent but more than 16 per cent, would not comply with s 93D(6) and should not be referred under s 93D(5) (and it may have been this aspect of Miller J's decision which prompted the amendment to reg 19J and Form 22). However, we agree with Miller J that there is nothing in the material provisions of the Act which should be taken to have the effect that, simply because the worker ticked the "not less than 30%" box in a case in which that level is supported by a medical practitioner's opinion, the review officer is precluded from finding, on the whole of the evidence presented to him, that the relevant level is less than 30 per cent but 16 per cent or more.

42 As to McMullen, we have said that, at least in the ordinary case, it is impermissible to ascertain the intention of the legislature as expressed in a statute by reference to the terms of a regulation which has been amended some time after the statutory provisions came into effect (unless, which is not this case, the regulations are expressed by the empowering provision to be read as if enacted in the Act). That is so regardless of what might have provoked the amendment. However, that was the approach which was adopted in McMullen. In our respectful opinion, the Court was plainly wrong in adopting it and it seems to us that the error infected the conclusion at which the Court ultimately arrived. We are consequently of the opinion that McMullen should be overruled and we decline to follow it.

43 It follows, from our decision in respect of ground B, that the retrospectivity issue falls away. The conclusion that McMullen was wrongly decided has the consequence that the decision of the Review Officer should stand regardless of whether or not the new regulations had taken effect. Moreover, it did not matter whether or not the original form or the new form was used, the worker having in any event nominated only one level of disability. There is consequently no need for us to deal with ground A.

44 It follows from what we have said that we would uphold ground B, reject the arguments raised by the notice of contention, allow the appeal, set aside the decision of the Compensation Magistrate and restore the decision of the review officer.

• Relevant structure of the Act
• The amendment of reg 19J and the cases of Ivey and McMullen
• Events in this case
• The decision of the Compensation Magistrate
• Grounds of appeal and notice of contention
• The referral issue
• The retrospectivity issue
• Conclusion