Williams v Muller

THE ISSUES 9 It is common ground that on 17 May 2002 Mr Williams and Comcare agreed that an independent medical specialist should prepare a report on the question whether Mr Williams' employment had contributed to his diabetes, and that each party would be bound by the independent specialist medical opinion on that question. There is also no dispute that Professor Cohen was selected by Comcare as an independent medical expert, with the approval of Mr Williams. What is in issue is, apparently, the precise terms of the agreement, and whether it remains in force in respect of Professor Cohen's report. 10 Mr Williams has taken the view that Professor Cohen's report responds to the issue which he was required to address in terms favourable to Mr Williams' claim. Consequently, he is insisting upon Comcare honouring the agreement, and determining or submitting to a determination that his diabetes is compensable under the SRC Act. Comcare is not prepared to do so. Comcare's position is first that the agreement included terms that: · the parties were to prepare a common list of questions, raising the question of the causation of Mr Williams' diabetes, and a common set of documents for submission to Professor Cohen; · a common list of questions and a common set of documents were to be submitted to Professor Cohen for his opinion; and · Professor Cohen's opinion would be treated by the parties as determining the matter. 11 Comcare then alleges that Mr Williams departed from the agreement when his solicitors forwarded on 22 July 2002 his questions, together with what was described to be a statement of the relevant law, directly to Professor Cohen. Consequently, as I understand its position, Comcare claims it was not bound by the agreement by reason of Mr Williams having so departed from the agreement. Mr Williams' solicitors sent a copy of the material he submitted to Professor Cohen by letter to Comcare on 29 July 2002. 12 Subsequent to Mr Williams' solicitors communicating directly with Professor Cohen, on 31 July 2002 Comcare also communicated directly to Professor Cohen enclosing the material which it requested him to consider, and a series of questions for him to address. Comcare anticipated an argument that, by that conduct, it may be said to have agreed to a variation of the original agreement. However, it contends that there was no agreed variation to the original agreement because, in the circumstances, there was no meeting of minds required for such a variation to the original agreement as the solicitor then acting for Comcare did not consider, or appreciate the significance of, the legal analysis included in the material submitted to Professor Cohen on behalf of Mr Williams, and which Comcare says is incorrect. 13 The next step in Comcare's contentions is premised on the basis that there is found to have been an agreed variation to the agreement by the events referred to in the preceding paragraph. It contends that the agreement as varied was on the following terms: · the parties were separately to put questions to Professor Cohen on the causation of Mr Williams' diabetes, supported by separate documentation; · the separate questions were in quite different terms, both in form and in substance; · Professor Cohen's report was '"proposed as the final arbiter of the matter" and the parties "proposed to abide by [his report] (although they are not bound to do so)"'. 14 Comcare further alleges that, whatever the terms of the varied agreement, there were critically missing terms so that it was unenforceable. It is asserted that no agreement was made between the parties as to how Professor Cohen's answers to one set of questions were to be reconciled with his answers to the other set of questions. It is asserted that there was no agreement that the contentions of law put forward on behalf of Mr Williams relating to causation were to be treated by Professor Cohen as 'definitive' or that, to the extent to which his responses were moulded by that version of the law, they were to be taken as determining Comcare's liability to pay compensation to Mr Williams under the SRC Act.

15 The next contention of Comcare was that Professor Cohen's report does not address the critical question as to Comcare's liability under the SRC Act in terms required by the SRC Act. It contends that the agreement (whether in its original or its varied form) did not include a promise by Comcare to accept liability to pay compensation to Mr Williams in circumstances outside those contemplated by the SRC Act. It is then said that Professor Cohen's report goes no higher than proposing, as a reasonable hypothesis, that a causal connection existed between Mr Williams' diabetes and his employment via 'his living circumstances … and the changed lifestyle'. Comcare asserts that Mr Williams' living circumstances whilst in the RAAF and the changed lifestyle they involved were not features of his employment, that is they were not elements or features of his duties as a member of the RAAF. Hence, the argument runs, Professor Cohen's report does not express an opinion, which in terms of the SRC Act addresses the causation relationship of Mr Williams' diabetes with his service with the RAAF. 16 Finally it is contended that, in the event that an agreement were made between Comcare and Mr Williams for the compromise of his claim for compensation in the terms asserted by or on behalf of Mr Williams, it is not legally enforceable because Comcare can only be liable to pay compensation to Mr Williams in respect of his diabetes if his diabetes was contributed to in a material degree by the performance of his duties as a member of the Defence Force. Comcare, it is argued, has no legal capacity to pay any money to Mr Williams except where that money is required to discharge a liability incurred by Comcare under the SRC Act. If the opinion of Professor Cohen exposes Comcare to the contractual obligation to pay compensation to Mr Williams, where that exposure is not in accordance with the SRC Act, then Comcare cannot lawfully accept his claim. Reliance was placed upon the decisions in Behan v Australian Telecommunications Corporation (1990) 26 FCR 337; Australian National Railways Commission v Commission for the Safety, Rehabilitation and Compensation of Commonwealth Employees (1992) 35 FCR 344; and Hardin v Comcare Australia (1995) 21 AAR 392.

the evidence and findings of fact 17 It is clear that on 17 May 2002 Comcare and Mr Williams agreed upon the engagement of an independent medical specialist to address the question required to be addressed by the SRC Act as to whether his diabetes was, in the relevant sense, caused by his employment. It is also clear that the parties agreed to be bound by the opinion of that independent medical specialist. Subsequently, the selection of the independent medical specialist was determined as Professor Cohen. 18 It is further clear on the evidence that the intention of that agreement was to adopt a process for determining the 'causation' issue without having the case heard by the Tribunal. The context in which the agreement came to be made (see Codelfa Construction Pty Ltd v State Rail Authority of New South Wales (1982) 149 CLR 337 per Mason J as he then was, at 352) was that there were conflicting medical opinions on whether Mr Williams' employment had contributed in a material way to the onset of his diabetes. In its review decision made on 27 May 2001 (as contained in the s 37 statement) Comcare noted the conflicting medical reports provided to Comcare and to Mr Williams regarding the relationship of his employment to his diabetes. The report indicates that Comcare was satisfied that there was no causal connection between the diabetes and the service employment. It regarded the medical opinion in favour of that connection as being no more than mere conjecture. Consequently the determination of 20 September 1999 was affirmed and the claim for compensation under the SRC Act refused. Hence, the causation issue was then the stumbling block, or the reason, for Comcare not accepting the claim. 19 The evidence about what happened at the teleconference meeting on 17 May 2002 is sparse. The lawyer attending the meeting on behalf of Mr Williams contemplated that the agreement would be reflected by appropriate binding orders of the Tribunal, but it is unclear whether that is simply an understanding, or was the result of a particular discussion. His evidence of what was said at the conference is very limited. The lawyer attending the conference on behalf of Comcare provides a more detailed description of what transpired during that meeting. I accept his evidence. It is not a verbatim record of the conference, but based upon notes of a series of steps in the discussion. The course of discussion involved identifying the condition of Mr Williams, then the Tribunal member suggesting that the condition of diabetes may be the result of a combination of genetic predisposition together with a triggering factor, and some review of the parties' respective medical specialists' opinions. It was in the light of the discussion to that point that the possibility of an independent medical specialist being appointed to prepare a report on the causation issue arose, and there was discussion as to how that medical specialist should be selected. There was also discussion, but without agreement on the topic, as to whether the independent specialist when selected should examine Mr Williams. 20 At that point the officer of Comcare attending suggested the independent specialist 'could be provided with' the documentation along with an agreed set of questions. The parties agreed to be bound by the opinion of the specialist as to whether Mr Williams' employment in the RAAF had contributed to his development of diabetes. The hearing was then adjourned. 21 The next conference at the Tribunal was on 19 July 2002. By that time Professor Cohen had been agreed as a suitable independent specialist. The second meeting involved the lawyer for Comcare indicating that a copy of the questions proposed to be put to Professor Cohen by Comcare had been forwarded by its solicitors the Australian Government Solicitor (the AGS) to Mr Williams' solicitors Ward Keller some time earlier for consideration. The lawyer for Mr Williams indicated that there had been a delay in preparing the questions to be asked on behalf of Mr Williams, pending further information from Mr Williams' medical adviser. The lawyer for Comcare then said: 'I proposed, as a practical consideration, to forward a single bundle of documents to the professor for his consideration. I also said that this would be done after Mr Williams' solicitors had provided me with a copy of the applicant's series of questions.' 22 He does not claim that there was specific assent to that proposal, but there was no disagreement with it. There is no other direct evidence as to the nature of that communication. 23 There was no further hearing of the Tribunal before Professor Cohen's report on 28 August 2002. 24 The original proposal was in effect for the independent medical examination to be a 'casting vote' or the final arbiter of the question of fact which involved medical expertise, namely whether Mr Williams' diabetes was contributed to in a material way by his service with the RAAF.

25 In his oral evidence, the lawyer for Comcare indicated that he had the view that it would be 'more practical' for one set of questions than for two sets of questions to be submitted to Professor Cohen, and until notified by the lawyers for Mr Williams that they had written directly to Professor Cohen, he had assumed, because it had been raised a number of times previously, that Comcare's solicitors would be the communication line to Professor Cohen. Comcare had engaged Professor Cohen. He had said he would bundle up the set of documents and would pay the costs. He had discussed the sort of documents which would be provided to Professor Cohen. 26 The Tribunal records do not throw any real light upon the detail of conversation at either of its hearings. 27 There was extensive correspondence between the parties following the meeting of 17 May 2002. It is appropriate to note some of it in a little detail. 28 On 6 June 2002 the AGS wrote to Ward Keller suggesting Professor Cohen as the medical expert. The letter included the following: 'We confirm that the Respondent has agreed to bear the cost of the preparation of a report. We propose to provide the Independent Medical Specialist with a copy of the "T-documents", copies of additional reports prepared since provision of said "T-documents" together with a complete copy of the Applicant's Service Medical Records. In the interests of practicality, we propose to provide the specialist with a copy of the Respondent's Questions for Independent Medical Specialist together with any additional series of questions the Applicant prepares. Upon receipt of the report we shall file it with the Tribunal and serve a copy upon the Applicant.' 29 The preceding day the AGS had written to Ward Keller enclosing a copy of Comcare's proposed questions for the independent medical specialist. The letter acknowledged that Mr Williams may wish to prepare his own series of questions to be put to the specialist, and asked for a copy of them. On 12 July 2002 Ward Keller wrote to the AGS indicating that they were still liaising with the medical specialist treating Mr Williams so as to formulate questions which they wished to submit to Professor Cohen.

30 In the meantime, following the letter of 6 June 2002, Ward Keller wrote on 18 June 2002 to the AGS indicating agreement to the appointment of Professor Cohen, and requesting that Professor Cohen speak to Mr Williams prior to preparing his report. The letter added the following: 'We refer to our recent correspondence in relation to the issue of an appropriate expert to review our client and prepare a report in this matter. We confirm that the parties will treat the report as determining the matter. That is, if the report indicates that Mr Williams' employment cannot be said to be a material contributing factor to his developing the disease, he will not pursue the claim further. On the other hand if the medical report indicates that Mr Williams military service could have been a material contributing factor, then the Commonwealth will accept liability and reverse its earlier decision.' (my emphasis) The causation requirement, by reason of the definition of disease, is incorrectly stated. It is whether the disease was (not, could have been) contributed to in a material degree by the employment. 31 AGS responded to that letter on 16 July 2002. It confirmed that the parties were to treat Professor Cohen's report 'as determining the matter'. It made some observations about the views on causation in Ward Keller's letter of 18 June 2002. It correctly made the point that it must be established that it is more likely than not that Mr Williams' employment contributed in a material degree to the development of his diabetes. It therefore enclosed a refined set of questions to be put to Professor Cohen for consideration by Mr Williams' lawyers. It disagreed that Professor Cohen should communicate directly with Mr Williams prior to the preparation of his report. In the event, he did not do so. 32 That letter also added 'as a practical measure' the proposal that Professor Cohen be provided with a single bundle of documentation together with a covering letter enclosing the respective series of questions to be asked on behalf of Mr Williams and on behalf of Comcare. It therefore asked that Mr Williams' solicitors provide his formulated series of questions so the matter could progress, and so the AGS could arrange for documentation to be forwarded to Professor Cohen. In fact matters did not occur as then contemplated. As noted earlier, on 22 July 2002 Ward Keller wrote directly to Professor Cohen, and provided a copy of the letter to the AGS on 29 July 2002. I accept the AGS was taken by surprise by that step. The reaction was to write quickly and separately to Professor Cohen on 31 July 2002. 33 The letter to Professor Cohen from Ward Keller of 22 July 2002 enclosed a witness statement of Mr Williams, his service medical records (with comments upon them), and raised for consideration the possibility that a viral infection sustained during employment is one of the recognised triggers for the onset of diabetes. It asserted that Mr Williams resided in single men's quarters on base until his marriage in the early 1990's: 'Gary's residence on base (ie, at his place of employment) and in close proximity to his fellow servicemen on a 24 hour basis, is a factor that we ask you to note.' 34 The letter to Professor Cohen indicated that the purpose of the report is for Professor Cohen to 'act as a type of "referee's decision" which the parties propose to abide by (although they are not bound to do so)'. There has been no evidence explaining that parenthetical remark, but I find it does not represent the agreement between the parties. It is a loose remark. It is not one which prompted any reaction by Comcare or the AGS until these proceedings. 35 The questions put to Professor Cohen on behalf of Mr Williams were whether he was of the opinion that: '(1) Gary Williams developed [diabetes] at some time during his employment in the RAAF; (2) Are there are any factors or features of [his] employment with the RAAF (no matter how small - but providing the contribution is not insignificant) that may have contributed to [Mr Williams] developing a virus or being exposed to a recognised trigger, giving rise to his [diabetes]?' (my emphasis) 36 The letter contained a brief explanation of what was said to be the relevant law along the following lines: The fact or feature of the employment is not required to be the real proximate or effective clause of the disease or its development. If a link is established, it does not matter that the contribution to the link is large or small. It emphasised that the contributing factor must be some event or occurrence in the course of the employment or some characteristic of the work performed or the conditions in which it was performed. It made the point that those matters needed to be addressed on the balance of probabilities, so that the question is whether: '… it is probable that some factor of our client's employment contributed to his exposure to either or both of the requisite environmental or trigger factors, which lead to the development of his Type 1 diabetes.' The opinion was said to be required to be based on more than mere conjecture. The letter added: 'Provided there is some evidentiary basis for you to support your opinion, that is sufficient.' 37 The responsive following letter from the AGS to Professor Cohen of 31 July 2002 included a set of questions, the 'T - Documents' prepared for the Tribunal in accordance with s 37 of the AAT Act, and Mr Williams' service medical records. It noted that Professor Cohen had already received a set of questions and a bundle of documents from Ward Keller. It then continued: 'We request that you consider all documentation provided and prepare a written report that addresses the parties' respective questions. We confirm that the Professor's report is proposed as the final arbiter of the matter. We welcome any additional diagnosis considered relevant.' 38 There is no need to refer to the 19 questions submitted by the AGS to Professor Cohen. Many related to the general state of knowledge about diabetes, its aetiology and its progression, including the state of knowledge about the relevance of environmental events to those matters. In relation to Mr Williams' particular condition, questions 16 to 19 were in the following terms: '16. Do you agree that in the absence of direct serological proof of a potentially incriminating organism it must be assumed that Mr Williams would have developed diabetes regardless of his occupation? 17. In your opinion is there a causal connection between the diabetes suffered by Mr Williams and his employment with the army - that is to say, was there any feature of his employment which played a part in causing Mr Williams to develop diabetes? 18. In your opinion is it more likely than not that his employment contributed to his developing diabetes or is it: (a) merely a possibility; or (b) a matter of conjecture; or (c) unlikely that his employment materially contributed to his developing diabetes? 19. If it is your opinion that Mr William's employment contributed to the development of diabetes, is such contribution, in your opinion: (a) minimal; or (b) more than minimal; or (c) less than minimal?'

professor cohen's report 39 Professor Cohen's report of 28 August 2002 is a lengthy one. He indicated that he had not taken up the invitation to speak to either Mr Williams or his medical specialist. That is because the background to Mr Williams' illness from time to time is well documented. He also indicated that he proposed to progress 'from the general to the particular' and so to address the questions posed by Comcare before turning to those posed by Mr Williams. 40 In answer to the question posed by Comcare, he explained the current state of knowledge about the aetiology of diabetes, the factors which create a vulnerability to it, and its clinical processes. He noted that there is yet to be defined and isolated a single factor or material which, of itself, may be the sole cause of diabetes. He noted that viruses, as one environmental factor, are considered to cause diabetes, and he explained why. He said that while genetic predisposition seems to be necessary for the development of diabetes, non-genetic environmental factors play an important part in expression of the disease, including viruses as one environmental factor. He knew of no particular occupation which renders a person likely to develop diabetes. He knew of no particular environmental hazard which would enhance the likelihood of the development of diabetes. He considered each case needs to be considered on its merits (except perhaps for certain toxic chemicals). He then deferred answering questions 16 - 19 posed by Comcare until considering the particular clinical history and investigations concerning Mr Williams. 41 He confirmed the diagnosis of diabetes made on 2 October 1989. After referring at some length to the history obtained by reference to Mr Williams' service medical records, he stated that he had carefully examined those records. He concluded: 'There is sufficient evidence in both bundles of documents to validate a diagnosis of recurrent viral infections.' (The reference to 'both bundles of documents' is to the fact that both the AGS and Ward Keller had largely replicated Mr Williams' medical records).

42 Professor Cohen then turned to address the questions posed by Ward Keller. He noted Mr Williams' statement, including his previous excellent health, the deterioration in his health maintenance standards during his service, and his nine year residence in the single quarters 'and the temptations associated with this'. There does not appear to have been any dispute about that history, or any suggestion that it is not in accord with the information in the T-documents. He observed that Ward Keller are more interested in the 'physical propinquity of these circumstances'. In that regard, he noted references in the literature to the susceptibility of recruits and servicemen to viral infections. The material available to him did not indicate the type of virus to which Mr Williams during the 1980's had been vulnerable. 43 The first question posed by Mr Williams was readily answered. Mr Williams developed diabetes at some time during his employment in the RAAF. That is not disputed by Comcare. 44 The answer to question two (see [35] above) was a guarded 'yes'. He explained that, prior to enlistment, recurrent viral infections were not a feature of Mr Williams' health, but that it appears to have been a feature, from at least 1982 and up until and after the development of diabetes. He then continued: 'Hereby, I consider, the link is established and the secondary consequences of repeated infections of similar type only serve to reinforce the likelihood that repeated and sustained exposure to viral infections were occurring. As to whether this susceptibility to repeated viral infections related to his employment or the characteristics of the work performed or the conditions in which it was performed I can form no definite opinion for it is my impression that, apart from the propinquity of the single mens' quarters the nature of his employment and conditions in which it was performed were not untoward or unusual.' (Professor Cohen's emphasis) 45 He did not accept that mere service in the RAAF, or mere environmental exposure or stimulant in respect of that service could be incriminated. However, he said: 'However, the additional factor of repeated viral infections leading up to the emergence of the diabetes in a man who was not so predisposed prior to enlistment cause me to consider that there is a link "however large or small" which has been established in this particular case and set of circumstances.'

46 Professor Cohen then turned to the final three questions posed by Comcare listed at [38]. He did not return to question 16 except to the extent it was addressed at the end of his answer to question 17. His answers were as follows: '17. The causal connection between the development of the type 1 diabetes and his military service depends on the bouts of frequent viral infections from which he suffered from 1982 onwards over some seven years. There is nothing to suggest that he was so predisposed prior to enlistment although the need for submucosal resection in 1979 and the radiological evidence for a vestigial frontal sinus has been noted. The causal connection between the viral infections, the diabetes and the nature of his employment probably related to his living circumstances during the early period of his enlistment and the changed lifestyle which developed during this time. The obverse of this observation "would these circumstances have unfolded had he not been in the service?" are theoretical and cannot be answered. 18. In the light of the above I consider it more likely than not that his diabetes developed in consequence of his employment. In other words, I consider this to be a reasonable hypothesis. 19. The emergence of his diabetes was preceded by at least eight months of weight gain, hypertension, abnormal lipids and a significantly elevated blood glucose. This was at a time when he had "let himself go" in circumstances which are described in his affidavit as being part of the service life and mores to which he was committed by peer pressure. In this sense I consider that the development of his diabetes and its subsequent course were b) more than minimal.'

CONSIDERATION 47 The agreement made on 17 May 2002 seems to have been not fully thought out. The primary issue as to the relationship of Mr Williams' diabetes to his employment was agreed to be resolved in a certain way, but there was no express agreement as to the material upon which Professor Cohen should be asked to express his views, or precisely the questions which he should be asked to address. There was also no express agreement as to how Professor Cohen's report would lead to resolution of the AAT proceedings, that is whether it would result in some form of consent determination to be made by the AAT or whether it would result in Comcare reconsidering its earlier decision and making a decision in accordance with the opinion of Professor Cohen, or that something else would occur. Finally, it does not appear to have been considered what, if any, instruction Professor Cohen should have had as to the form of the applicable law. One issue which has now emerged is whether that which Professor Cohen identified (if he did) as contributing to the onset of diabetes was in fact, in terms of s 4(1) of the SRC Act, 'employment' of Mr Williams so that his ailment was contributed to in a material degree by his employment. 48 One would have expected such issues to have been expressly addressed. It may be that the latter issue was not expressly addressed because, to that point, Comcare had assumed that the exposure to environmental factors (Mr Williams' living in single men's quarters and his personal living habits as a result) were matters which related to his employment. That no longer seems to be the case. There are therefore two significant issues which underlay the agreement made on 17 May 2002. The first relates to procedural matters. The second to a substantive legal question. They are: (1) with respect to the opinion to be sought: (a) what information was to be provided upon which the questions were to be addressed; (b) precisely how the questions to be addressed were to be presented; (c) in the light of the opinion, how was it to be reflected in any determination by the Tribunal or otherwise; and (2) if it arose in the light of the opinion, whether all or any 'employment' factors which Professor Cohen identified as materially contributing to his diabetes as a matter of law were matters which constituted part of his employment. 49 My findings above indicate that I do not accept that it was an express term of the agreement of 17 May 2002, as asserted by Comcare, that the parties were to prepare a common list of questions raising the question of the causation of Mr Williams' diabetes, and to submit a common set of documents for consideration by to Professor Cohen. 50 However, as it is clear that the parties intended to enter into a binding agreement on 17 May 2002 in terms of [17] above, and that the agreement would not be effective without implication of certain terms into the agreement, I consider it appropriate to imply terms into the agreement so as to give it business efficacy. It is necessary to do so. Looked at objectively, it is clear that had the parties been asked at the time what they each intended, they would have responded in terms of what I propose to imply into the agreement, in effect that the implication 'goes without saying' (Codelfa (supra) at 347.) Moreover, the terms I imply into the agreement are clear, and consistent with the express terms of the agreement, and are reasonable and equitable. See generally The Corporation of the City of Adelaide v Jennings Industries Limited (1985) 156 CLR 274; Hospital Products Ltd v United States Surgical Corporation (1984) 156 CLR 41 at 117-118, and Secured Income Real Estate (Australia) Ltd v St. Martin's Investments Pty Ltd (1979) 144 CLR 596 at 605-606. 51 In my judgment it must be inferred, to give the agreement made on 17 May 2002 business efficacy, that Professor Cohen would have access to the information relevant to Mr Williams' employment and medical history which was available to the Tribunal in the T-documents. It must also be inferred that the questions which he was to be asked included the critical question of fact as to whether any 'employment' factors contributed in a material way to this development of diabetes (leaving aside the question of law whether those factors or any of them were factors which constituted his employment). It is difficult to see why such extensive questions were required to be submitted to Mr Cohen by Comcare. The question ultimately is one of fact, albeit one which might require expert medical opinion to address. It is the question which the Tribunal would have had to have decided on the basis of the evidence including expert medical opinion. It is whether his diabetes was contributed to in a material way by his employment by the Commonwealth. Professor Cohen was to be asked to accept the accuracy of the material in the T-documents, in particular Mr Williams' medical records and his personal history as recorded in those documents. There is no suggestion that that personal history or those medical records were contentious. 52 In the event, that implied term was complied with. Professor Cohen was asked to speak to Mr Williams, and to his medical specialist, but he did not do so. He based his opinion on the medical records of Mr Williams, and on his personal history in the relevant period from commencement of his RAAF service and prior to it. It is not suggested that the material contained in the statement submitted by Professor Cohen was different from, or inconsistent with, any of the information otherwise available to the Tribunal. Accordingly, subject to the medical opinion addressing the correct issue, in my judgment the implied term as to the material which was to be submitted to Professor Cohen for his opinion was complied with, or perhaps more accurately was not materially departed from. It was not materially departed from by the separate submission of material to Professor Cohen.

53 The questions submitted by Mr Williams (see [35] above) and by Comcare (see [38] above) are not in terms asking the question whether, on the balance of probabilities (and assuming the material submitted was correct and identified relevantly Mr Williams' personal, medical and employment history), Mr Williams' diabetes was materially contributed to by his employment with RAAF. I do not think it is necessary to imply that there should be one only question submitted to Professor Cohen, or that such questions as were submitted to him should be jointly presented. The important issue is whether Professor Cohen was asked his opinion on the relevant 'causation' question. The utility of the many questions asked by Comcare is not apparent to me, but in a real sense they were preliminary. As I noted, question two of the questions submitted by Mr Williams, asked whether there were any factors or features of his employment which may have contributed to him developing a virus or being exposed to a trigger giving rise to his diabetes. The question was not that agreed to be submitted. It was in a practical sense a preliminary question. If Professor Cohen had answered only that question, his opinion would not have been expressed in terms of the relevant question to be submitted. It would not have given effect to the agreement. However, question 17 of the questions put by Comcare is close to an accurate expression of the question agreed to be submitted. Question 18, in particular by use of the term 'more likely than not', accurately indicates to Professor Cohen the way in which he should address answering the question, as distinct from answering it on the basis of medical opinion with some stronger degree of certainty. The combination of questions 18 and 19 were, presumably, designed to establish a material contribution in the alternative that the employment contributed to the development of diabetes in a more than minimal way. 54 Hence, ultimately, in my judgment the questions as expressed included in a perhaps oblique way the correct question which was agreed to be submitted to Professor Cohen by the expression in questions 17, 18 and 19 of the questions put forward on behalf of Comcare. Despite the complexity of the questions submitted, I do not consider the mere fact of them being submitted from different sources or in the terms in which they were submitted involved such a breach of the agreement of 17 May 2002 as to lead to that agreement coming to an end. I also consider that there was no variation to the agreement on 22 or 31 July 2002 by the fact of the independent correspondence sent to Professor Cohen on behalf of Mr Williams and on behalf of Comcare or its content. I accept that the parties did not address how one set of answers of Professor Cohen to one set of questions were to be reconciled with his answers to the other set of questions. That is because, I think, the parties through their solicitors did not identify clearly and precisely what question or questions were to be asked of Professor Cohen. However, as I have found, it was implied in the agreement of 17 May 2002 what information was to be submitted to Professor Cohen and ultimately what question was to be answered by him. That information was submitted to Professor Cohen, and the correct question was (in the manner I have described) asked of him. 55 The contention of Comcare that Mr Williams breached the agreement by including a description of the relevant law in a way which is inaccurate is one I reject. I do not need to address it in detail. The question which was put to Professor Cohen by or on behalf of Mr Williams was, at least in the sense I have identified, inaccurate. As I have noted earlier, if only that question had been submitted, and answered, the question which was agreed on 17 May 2002 to be submitted to Professor Cohen would not have been submitted to him. The agreement would not have been performed. But the parties, for whatever reason, contemplated a series of questions being submitted. Question two submitted on behalf of Mr Williams was, as were many of the questions submitted by Comcare, preliminary only. If, despite having been asked the correct question (in the manner I have identified), Professor Cohen's opinion had only been responsive to question two as submitted by Mr Williams, then his opinion would not have been in response to the question which the agreement contemplated. It would not have obliged Comcare and Mr Williams to have been bound by it, at least as determining the 'causation' issue. As appears below, I have determined that Professor Cohen did answer the question which the agreement of 17 May 2002 intended that he should answer. 56 It is necessary to refer to the other issues which underlay the agreement made on 17 May 2002. If Professor Cohen said that factors A and B materially contributed to Mr Williams' diabetes, it is a matter of law whether such factors were part of Mr Williams' employment. There will be circumstances where there would be no contest about that issue, for example hearing loss caused by exposure to noise in employment. There will be other circumstances where the factors are clearly unrelated to the employment. It is no part of a medical opinion to determine the answer to such an issue. It was not intended by the parties that Professor Cohen should do so. In my view there was an underlying and unresolved issue to the agreement of 17 May 2002. It appears to have emerged only belatedly perhaps because Comcare had not identified it previously as it did not need to do so given its determinations, as to whether the 'environmental considerations' leading to Mr Williams developing multiple viral diseases, and in turn diabetes (if that is what Professor Cohen concluded) were in fact related to his employment. That is not a factual question dependent upon medical expert evidence, but a legal question in the light of the apparently uncontested facts that Mr Williams was in fact resident in single men's quarters until at least 1989, and that during that time he 'let himself go'. 57 In my judgment, to give the agreement of 17 May 2002 efficacy, there must be implied the term that, in the event that Professor Cohen were of the opinion, on the balance of probabilities, that certain matters or factors relating to Mr Williams' employment materially contributed to his diabetes, the matters or factors as a matter of law bring his claim within the definition of disease in s 4 of the SRC Act. In short, whether those matters or factors as a matter of law amount to the disease being contributed to in a material degree by his employment. The causation component of that definition will have been resolved by the opinion of Professor Cohen. The legal component, whether those causative matters or factors lead to whether the employment itself having materially contributed to the disease is a separate and different issue. Section 14(1) provides for liability in respect of 'injury' in certain circumstances, and 'injury' is defined to include a disease. In the case of an injury that is not a disease, the injury must arise out of or in the course of employment: see ss 6 and 6A. In the case of the disease, the causative requirement contained in the definition of 'disease' involves, in the present circumstances, two steps: whether the alleged factors did materially contribute to the disease, and whether these factors were part of or features or aspects of the employment. 58 Events which occur in the course of employment may mean that a disease was contributed to in a material way by the employment: see e.g. Federal Broom Company Pty Ltd v Semlitch (1964) 110 CLR 626 at 632, 641; Treloar v Australian Telecommunications Commission (1990) 26 FCR 316; Wiegand v Comcare Australia [2002] FCA 1464; (2002) 72 ALD 795. 59 That implied term, depending upon the opinion of Professor Cohen, may need to be determined by the Tribunal. For, in my judgment, the agreement of 17 May 2002 contemplated by necessary implication that Professor Cohen's opinion on the causation issue, if favourable to Comcare, would result in the application to the Tribunal being dismissed by consent. And, if his opinion on the causation issue were favourable to Mr Williams, would result in the Tribunal being asked to substitute a determination favourable to Mr Williams (in its discretion, then remitting to Comcare the function of determining the nature and amount of Mr Williams' entitlement under the SRC Act), subject to the legal issue arising to which I have referred. If Professor Cohen had identified causative factors which clearly were part of Mr Williams' employment, such an issue would pass sub silentio because the answer would be obvious. In this instance, Comcare has raised that issue and the Tribunal, depending upon Professor Cohen's opinion, may need to address it. 60 I find some difficulty in identifying how Professor Cohen addressed the critical question required to be addressed by him. That is because it was not put to him in terms. I have explained why that is so, namely as a consequence of the complex (in the case of Comcare) and inaccurate (in the case of Mr Williams) questions which were put to him on the issue. However, despite the way in which question two of Mr Williams' questions was framed, it appears (see [44]), that Professor Cohen addressed that question on the balance of probabilities and on the basis that it asked whether the diabetes in fact, rather than whether it may have, been caused or contributed to by his employment condition. Professor Cohen expressed the positive view that Mr Williams: 1. prior to his RAAF service was not predisposed to repeated viral infections; 2. subsequent to, and apparently by reason of, the nature of his living habits in single men's quarters, developed repeated viral infections; and 3. his susceptibility to repeated viral infections then led to his diabetes, at least as a material contributing factor to the onset of his diabetes.

The third of those steps was expressed to be a link 'however large or small'. 61 However, that understanding of Professor Cohen's report must be qualified. That is because elsewhere he expressed 'no definite opinion' as to step two, namely whether the susceptibility to repeated viral infections related to his employment, or the characteristics of the work performed, or the conditions in which it was performed. He expressed 'the impression' that Mr Williams' living in single men's quarters was the only feature of his employment which was or may have contributed to the repeated viral infections, although the fact of those viral infections itself appeared to be uncontentious. On the other hand, Professor Cohen expressed the view in answer to question 17 from Comcare that the cause or connection between the viral infections and the nature of his employment probably related to Mr Williams' living circumstances during the early period of his enlistment and the changed lifestyle which developed during this time. On that basis, he said it was more likely than not that his diabetes developed in consequence of his employment. He then added, in a sentence stressed by senior counsel for Comcare: 'In other words, I consider this to be a reasonable hypothesis.' A reasonable hypothesis may or may not indicate an expression of probability. It may involve a possibility rather than a probability. However, bearing in mind the context of the other answers, I think Professor Cohen's report should be understood as using the expression 'reasonable hypothesis', in a more technical sense rather than as contradicting or going back on what he had expressed as to probabilities in his opinion elsewhere. As he said at the conclusion of his report: 'Scientific discipline would demand more than the details available to me on which to base an unassailable opinion. I am very much aware however, not only because of the legalistic information provided by Ward Keller, but also my experience in addressing the putative correlations between war service and certain disease conditions in veterans. These demand a standard of proof which is not so rigorous as that required in the substantiation of a clinical connection which would withstand the most clinical scrutiny and broad evidential support. This setting has made me more comfortable in coming to the conclusions outlined above.' 62 Hence, in my judgment, Professor Cohen's opinion is that Mr Williams developed repeated viral infections only during the period of his employment with the RAAF in the 1980s, and that the repeated viral infections in a material way led to his diabetes. 63 What is left uncertain is the question of law which, as I indicated, has now emerged and which was underlying the agreement of 17 May 2002. It does not involve Professor Cohen's expert opinion. It is whether that which Professor Cohen has treated as causative to the repeated viral infections and so to the diabetes in fact gives rise to a liability to pay compensation under the SRC Act. Professor Cohen has identified the causative elements as Mr Williams' living circumstances during the early period of his enlistment and the changed lifestyle which developed during this time. He later described Mr Williams as having 'let himself go' because of part of his service life and mores to which he was committed by peer pressure. I am satisfied Professor Cohen has answered the 'causation' issue in a way that is favourable to Mr Williams' claim. 64 There remains therefore the legal question whether those factors are or were part of or a feature of Mr Williams' employment with the RAAF so that he suffered a 'disease' as defined in s 4 of the SRC Act. 65 That is a matter which the Tribunal must answer. It may do so, subject to the parties' agreement, on the material it presently has. The parties may wish to adduce further evidence. Once the answer is given to that question, Professor Cohen's opinion should, in accordance with the agreement of 17 May 2002, be applied to determining the liability or otherwise of Comcare to pay compensation to Mr Williams in respect of his diabetes. In that regard, reference may be made to Mason v Social Welfare Department [1974] VR 506; Treloar (supra); Roncevich v Repatriation Commission [2003] FCAFC 146. 66 In the light of those conclusions, it is unnecessary to address the fourth contention of Comcare. It is not suggested that it was beyond Comcare's power to enter into the agreement to abide by a specialist medical opinion on a question as to its liability which is a question of fact requiring specialist medical opinion. The argument was that Comcare could not enter into an agreement which gave rise to a liability which it was not entitled to accept under the SRC Act. If the causation issue were determined in a certain way, as it has been, it is within the power of Comcare to accept the claim or for the Tribunal to accept the claim. What has arisen is the question whether what Professor Cohen has identified as the relevant 'employment' related causative factors are in fact employment related. If, as a matter of law, they are not employment related, then the claim must be rejected, and Comcare would not accept the claim. 67 The orders I propose to make are therefore: 1. to declare that the parties are bound by their agreement made on 17 May 2002 to accept as a fact that the Type 1 diabetes mellitus now suffered by Mr Williams was contributed to in a material way by him developing viral infections and vulnerability to viral infections during the period of his service in the Royal Australian Air Force, and that matters concerning his living circumstances during his period of enlistment from about 1980 and the changed lifestyle which developed during that period contributed in a material way to the diabetes now suffered by Mr Williams; and 2. the matter be referred to the Administrative Appeals Tribunal to determine in such manner as it may determine whether, in the light of the opinion of Professor Cohen of 28 August 2002, the onset of repeated viral infections and hence diabetes which was contributed to by Mr Williams' living circumstances from about 1980 and the changed lifestyle which developed during that period were features of or were part of or a consequence of his employment with the Royal Australian Air Force. 68 In the circumstances, it seems to me appropriate that there should be no order as to costs but I will hear the parties further before determining that issue. I will also give the parties leave to make submissions as to the precise form of the orders I should make to give effect to these reasons.

I certify that the preceding sixty-eight (68) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Mansfield.

Counsel for the Applicant: Mr C McDonald QC with Mr G Clift

Counsel for the Respondents: Mr P Hanks QC with Ms E Ford

Solicitor for the Respondents Australian Government Solicitor