1 HIS HONOUR: On 11 February 1999 I delivered judgment, finding for reasons then published, that the first defendant was in breach of its duty of care to the plaintiff in two ways:
"(a) In the failure following the presentation in February and March 1983 of the material identified in para 234 of this judgment to take the steps identified in paras 247 and 248 of this judgment;
(b) In the failure following receipt of the notification in May 1984 to attend promptly to the matters addressed in para 516 of this judgment."
2 Subsequently, on 11 March 1999, I ordered that there be a separate trial of the issue as to whether those breaches of duty, or either of them that I found established, were or was causative of harm. For the purposes of the determination of this issue only, it was to be assumed that the plaintiff is suffering from a psychiatric disorder.
3 At the trial of that further issue medical evidence was introduced and argument was directed to the issue of causation, and in particular to the onus of proof. It was submitted by Mr Shand of Queen's Counsel on behalf of the plaintiff that my findings of breach of duty, when coupled with evidence of harm suffered by the plaintiff at a point of time after such breaches, in what Mr Shand submitted was the very area of risk which the first defendant's duty was designed to avoid, imposed an onus upon the first defendant to prove that the harm suffered by the plaintiff was not caused by its negligence. Mr Shand submitted that a consideration of the authorities to which I was taken led to the conclusion that there was such a shift in the onus of proof. Mr McAlary of Queen's Counsel, on the contrary, submitted that the burden of proof rested upon the plaintiff throughout to establish that the negligence proved caused him harm.
4 These competing submissions obviously go to an issue of the utmost importance and warrant the closest consideration of the relevant authorities.
5 I was referred by counsel in the course of submissions to the following cases: Betts v Whittingslowe (1945) 71 CLR 637; McGhee v National Coal Board [1972] 3 AER 1008; Wilsher v Essex Area Health Authority [1988] 1 AC 1074; March v E & M H Stramare Pty Limited (1991) 171 CLR 506; Bennett v Minister for Community Welfare (1992) 176 CLR 408; Sellars v Adelaide Petroleum NL & Ors (1992-94) 179 CLR 332; Farrell v Snell (1990) 72 DLR (4th) 289; and Chappel v Hart (1998) 156 ALR 517.
6 Mr Shand submitted that what Lord Wilberforce said in McGhee as to a reversal of onus underlies the recent decision of the High Court in Chappel v Hart. Mr Shand's fundamental submission was expressed in the course of argument (T68):
"It is our submission that the Lord Wilberforce propositions are now installed as basic principles in respect of this sort of case where the negligence involves not a positive act but an omission, and particularly where there is involved an impossibility of the plaintiff proving in its own case, in effect, by some hypothesis that namely the damage would not have occurred apart from the negligence of the defendant."
7 I begin my review of the authorities with Bonnington Castings Limited v Wardlaw (1956) AC 613. The House of Lords had occasion to consider the onus of proof of damage in a case in which the injured worker was exposed by the use of a pneumatic hammer to silica dust. He was also exposed to such dust by swing grinders. There was no practicable way of providing dust extraction measures for the hammer, but dust extraction equipment was fitted to the swing grinders. This particular equipment was not kept free of obstruction and the employer was accordingly in breach of the relevant statutory duty. Having contracted pneumoconiosis, the worker sued his employer. It was determined in the House of Lords that the onus was upon the worker to prove that the breach of statutory duty caused or materially contributed to the injury suffered and not merely that it was possible that it did. In so deciding, the House of Lords overruled the judgment of the Court of Appeal in Vyner v Waldenberg Brothers Limited [1946] KB 50 where it had been determined that once a breach of statutory duty was proved and a workman was injured in a way that could result from the breach, there was a shift in the onus of proof and it was for the employer to prove that the breach was not the cause of the injury suffered.
8 In his speech in Bonnington Castings Lord Tucker said of the proposition that there was a shift in the onus of proof (at 624):
"My Lords, I think it is desirable that your Lordships should take this opportunity to state in plain terms that no such onus exists unless the statute or statutory regulation expressly or impliedly so provides, as in several instances it does. No distinction can be drawn between actions for common law negligence and actions for breach of statutory duty in this respect. In both the plaintiff or pursuer must prove (a) breach of duty and (b) that such breach caused the injury complained of. (See Wakelin v London & South Western Railway Co. (1886) 12 App.Cas. 41; 3 TLR 233) and Caswell v Powell Duffryn Association Collieries Ltd [1940] AC 152, 55 TLR 1004; [1939] 3 All ER 722.) In each case it will depend upon the particular facts proved and the proper inferences to be drawn therefrom whether the pursuer has sufficiently discharged the onus that lies upon him."
9 See also the speeches to the like effect of Lord Reid at 620 and Lord Keith at 625.
10 The principles as to the burden of proof as stated in Bonnington Castings were given further expression in the High Court in St George Club Limited v Hines (1962) Argus Law Reports 39. In their unanimous decision in this case, Dixon CJ, Kitto, Taylor, Menzies and Windeyer JJ said:
"In an action at law a plaintiff does not prove his case merely by showing that it was possible that his injury was caused by the defendant's default (Bonnington Castings Ltd v Wardlaw [1956] 1 All ER; [1956] AC 613); nor does proof of default followed by injury show that the default caused the injury, for as Viscount Simonds said in Quinn v Cameron and Roberton Ltd [1957] 1 All ER 760; [1958] AC 9, at p 23: '"Post hoc, ergo propter hoc" is a fallacy in respect of a breach of a statutory regulation as it is in respect of any other event in life'."
11 I turn now to McGhee. This was a case in which the appellant was suffering from dermatitis found to be due to the working conditions at the brick kiln where he was employed. The evidence also established that after work the appellant had to ride his bicycle home with brick dust adhering to his skin because there were no adequate washing facilities provided by the employer. The appellant's action at trial failed because he had not shown that the respondent's negligence in failing to provide washing facilities had caused his injury since there was no positive evidence that it was more probable than not that the appellant would not have contracted dermatitis had appropriate washing facilities been provided. The appellant succeeded in the House of Lords on the basis that the respondent's breach of duty had materially contributed to the harm suffered.
12 This was the setting in which Lord Wilberforce considered the issue of the onus of proof at pp 1012-1013:
"But the question remains whether a pursuer must necessarily fail if, after he has shown a breach of duty, involving an increase of risk of disease, he cannot positively prove that this increase of risk caused or materially contributed to the disease while his employers cannot positively prove the contrary. In this intermediate case there is an appearance of logic in the view that the pursuer, on whom the onus lies, should fail - a logic which dictated the judgments below. The question is whether we should be satisfied in factual situations like the present, with this logical approach. In my opinion, there are further considerations of importance. First, it is a sound principle that where a person has, by breach of duty of care, created a risk, and injury occurs within the area of that risk, the loss should be borne by him unless he shows that it had some other cause. Secondly, from the evidential point of view, one may ask, why should a man who is able to show that his employer should have taken certain precautions, because without them there is a risk, or an added risk, of injury or disease, and who in fact sustains exactly that injury or disease, have to assume the burden of proving more: namely, that it was the addition to the risk, caused by the breach of duty, which caused or materially contributed to the injury? In many cases of which the present is typical, this is impossible to prove, just because honest medical opinion cannot segregate the causes of an illness between compound causes. And if one asks which of the parties, the workman or the employers should suffer from this inherent evidential difficulty, the answer as a matter in policy or justice should be that it is the creator of the risk who, ex hypothesi, must be taken to have foreseen the possibility of damage, who should bear its consequences.
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And I must say that, at least in the present case, to bridge the evidential gap by inference seems to me something of a fiction, since it was precisely this inference which the medical expert declined to make. But I find in the cases quoted an analogy which suggests the conclusion that, in the absence of proof that the culpable condition had, in the result, no effect, the employers should be liable for an injury, squarely within the risk which they created and that they, not the pursuer, should suffer the consequence of the impossibility, foreseeably inherent in the nature of his injury, of segregating the precise consequence of their default."
13 In Wilsher, the House of Lords allowed an appeal from the Court of Appeal. Sir Nicholas Browne-Wilkinson was in the minority in the Court of Appeal but his judgment on causation was approved in the House of Lords. In the course of that judgment appears this passage:
"To the extent that certain members of the House of Lords (in McGhee) decided the question on inferences from evidence or presumptions, I do not consider that the present case falls within their reasoning. A failure to take preventative measures against one out of five possible causes is no evidence as to which of those five caused the injury."
14 In Wilsher the House of Lords considered McGhee and Lord Bridge of Harwich, with whom the other members of the House agreed, rejected the notion that McGhee had established a reversal of onus. Lord Bridge said, in referring to the speech of Lord Wilberforce, at 1087:
"My Lords, it seems to me that both these paragraphs, particularly in the words I have emphasised, amount to saying that, in the circumstances, the burden of proof of causation is reversed and thereby to run counter to the unanimous and emphatic opinions expressed in Bonnington Castings Ltd v Wardlaw [1956] AC 613 to the contrary effect. I find no support in any of the other speeches for the view that the burden of proof is reversed and, in this respect, I think Lord Wilberforce's reasoning must be regarded as expressing a minority opinion."
15 Lord Bridge later, after a review of the other speeches in McGhee, said at 1090:
"The conclusion I draw from these passages is that McGhee v National Coal Board [1973] 1 WLR 1 laid down no new principle of law whatever. On the contrary, it affirmed the principle that the onus of proving causation lies on the pursuer or plaintiff. Adopting a robust and pragmatic approach to the undisputed primary facts of the case, the majority concluded that it was a legitimate inference of fact that the defenders' negligence had materially contributed to the pursuer's injury. The decision, in my opinion, is of no greater significance than that and to attempt to extract from it some esoteric principle which in some way modifies, as a matter of law, the nature of the burden of proof of causation which a plaintiff or pursuer must discharge once he has established a relevant breach of duty is a fruitless one."
16 This brings me to the decision of the Supreme Court of Canada in Farrell. Shortly the facts were that the plaintiff lost the sight of an eye after an operation by the defendant surgeon. The medical evidence was that the operation was a possible cause of the loss of the sight but the evidence fell short of saying that it was the principal cause. The plaintiff succeeded at trial and on appeal. It was in such setting, and after the trial judge had determined that the defendant carried the onus of disproving that the operation caused the sight loss, that the appellate court considered the question of onus. In so doing express consideration was given to the speech of Lord Wilberforce in McGhee and to the later speech of Lord Bridge in Wilsher. In the course of the judgment of the court, consideration was given to the adequacy of the traditional approach to causation, particularly in the setting of cases of medical malpractice. However, ultimately the court rejected the concept of a shift of the onus of proof and it was said at 301:
"The legal or ultimate burden remains with the plaintiff, but in the absence of evidence to the contrary adduced by the defendant, an inference of causation may be drawn, although positive or scientific proof of causation has not been adduced."
17 How has the relevant law developed in Australian since Wilsher?
18 In March an intoxicated motorist travelling at an excessive speed came into collision with the defendant's truck which had been left at night obstructing the roadway. In the High Court the defendant's negligence was found to have been causative of the accident and the decision of the intermediate appellate court that the plaintiff's negligence was the sole effective cause of the accident was reversed.
19 In March the only references to Lord Wilberforce's speech in McGhee appears in the judgment of Mason CJ, not by way of adopting the proposition that there was a reversal of onus, but in the following context (at 514-515):
"Nonetheless, the law's recognition that concurrent or successive tortious acts may each amount to a cause of the injuries sustained by a plaintiff is reflected in the proposition that it is for the plaintiff to establish that his or her injuries are 'caused or materially contributed to' by the defendant's wrongful conduct: Duyvelshaff v. Cathcart and Ritchie Ltd. (1973) 47 ALJR 410, per Gibbs J. at p 417; 1 ALR 125, at p 138; Tubemakers of Australia Ltd. v. Fernandez (1976) 50 ALJR 720, per Mason J. at p 724; 10 ALR 303, at p 310; Bonnington Castings Ltd. v. Wardlaw (1956) AC 613, per Lord Reid at p 620; McGhee v. National Coal Board (1973) 1 WLR 1, at pp 4, 6, 8, 12; (1972) 3 All ER 1008, at pp 1010, 1012, 1014, 1017-1018. Generally speaking, that causal connection is established if it appears that the plaintiff would not have sustained his or her injuries had the defendant not been negligent: see I.C.I.AN.Z. v. Murphy (1973) 47 ALJR 122, at pp 127-128. But, as the decision in that case illustrates, it is often extremely difficult to demonstrate what would have happened in the absence of the defendant's negligent conduct.
Causation as a question of fact
The common law tradition is that what was the cause of a particular occurrence is a question of fact which 'must be determined by applying common sense to the facts of each particular case', in the words of Lord Reid: Stapley [1953] AC, at p 681. That proposition is supported by a long line of authority in the United Kingdom: Leyland Shipping Co [1918] AC, at pp 363, 369-370; Admiralty Commissioners v SS Volute [1922] 1 AC 129, at p 144; Yorkshire Dale Steamship Co [1942] AC, at p 706; Alphacell Ltd v Woodward [1972] AC 824, at p 847; McGhee v National Coal Board [1973] 1 WLR, at pp 5, 11; [1972] 3 All ER, at pp 1011, 1017. It is supported also by this Court's decision in Fitzgerald v Penn (1954) 91 CLR 268."
(The Chief Justice cited references to the speeches of the various members of the House of Lords in McGhee in the references to that case.)
20 After March the Full Court of the Supreme Court of South Australia considered the issue of causation in Pibworth & Anor v Roberts Pty Limited & Ors (1994) 176 LSJS 39. I do not propose to refer to the facts in that case, but in his judgment, with which Perry and Mullighan JJ agreed, Legoe A-CJ considered McGhee, Wilsher and March. His Honour commented on Wilsher at pp 11-12 of his judgment:
"I make reference to the speech of Lord Bridge in Wilsher v Essex Area Health Authority [1988] AC 1074. Lord Bridge stated four propositions of law relating to causation. Those propositions are summarised by the commentator in Cambridge Law Journal (1988) at 350 as follows:
'1. The burden of proving causation rests throughout a case upon the plaintiff. See Bollington Castings Ltd v Wardlaw [1956] AC 613.
2. Exceptional cases apart, the plaintiff must show that the defendant has caused or materially contributed to the injury; see Bollington Castings Ltd supra.
3. The law does not equate the situation where the defendant had "materially increased the risk of injury" with one where he had materially contributed to the injury.
4. That in some circumstances if it were proved that the defendant did "materially increase the risk" of injuring the plaintiff then the court might infer causation, ie that the defendant's negligence "materially contributed" to the injury.'
Lord Bridge's speech, which was approved by the other Law Lords in that case, resolved an issue that had been debated in England ever since McGhee v National Coal Board [1973] 1 WLR 1 which it was thought by many had introduced a benevolent principle of causation into the law of negligence allowing the court to 'bridge the evidential gap' where factual uncertainty made a decision about cause and effect impossible on the balance of probabilities. A judge in Fitzgerald v Lane [1987] 3 WLR 249 at 262 per Nourse LJ put it thus 'a benevolent principle smiles on…factual uncertainties and melts them all away.' Lord Bridge denied that the decision in McGhee had introduced any such new principle of causation into the law of negligence. The Court of Appeal (majority) was reversed by the House of Lords. In my opinion the reasons expressed by Lord Bridge are consistent with the principles as stated by the High Court of Australia."
21 In Bennett the facts were that a ward of state was injured while using an inadequately guarded saw, in circumstances in which he would have been entitled to damages against the responsible Minister. It was conceded that he would have sought such damages if he had known of his entitlement. It was accepted that the Director of Community Welfare had a duty to obtain independent legal advice for the ward in relation to his entitlement. The Director failed to discharge that duty and the claim became statute barred. The ward did obtain legal advice before the limitation period expired but was wrongly advised he had no cause of action against the Minister. He later sued for the Director's failure to obtain independent legal advice. It was held that the Director's breach of duty remained causative notwithstanding that wrongful advice was later obtained.
22 In their joint judgment Mason CJ, Deane and Toohey JJ referred not to the speech of Lord Wilberforce in McGhee but to the speech of Lord Simon of Glaisdale. That reference was in the course of determining that it was not necessary for the court to consider what would have been the position if the advice which the ward did obtain constituted independent legal advice that conformed to normal standards and procedures. Their Honours said at 416:
"Whether such advice would have constituted the supervening cause or a concurrent cause along with the Director's omission to obtain advice is an interesting and, on the facts as we see them, an academic question. In order to answer that question, it might be necessary to consider the view that there is no real distinction between breach of duty and causation (See McGhee v. National Coal Board (1973) 1 WLR 1 , per Lord Simon of Glaisdale at p 8; Quigley v. Commonwealth (1981) 55 ALJR 579 , per Stephen J. at p 581; 35 ALR 537 , at p 539), as well as the question whether a failure to take steps which would bring about a material reduction of the risk amounts to a material contribution to the injury. These questions have been considered in Canada in the context of a possible shift in the onus of proof (Nowsco Well Service Ltd. v. Canadian Propane Gas and Oil Ltd. (1981) 122 DLR (3d) 228; Letnik v. Metropolitan Toronto (1988) 49 DLR (4th) 707; Haag v. Marshall (1989) 61 DLR (4th) 371; Snell v. Farrell (1990) 72 DLR (4th) 289; Lankenau Estate v. Dutton (1991) 79 DLR (4th) 705) but it seems that the problem still awaits final resolution. There is no occasion to consider it here."
23 Gaudron J said at 420-421, in a passage upon which Mr Shand placed much reliance:
"Leaving aside cases involving some positive act and those in which an omission can be treated as a positive act, a case based on omission or a failure to act will, in certain respects, fall for analysis in a way that differs from that appropriate for a case based on a positive act. Thus, in the case of a positive act, questions of causation are answered by reference to what, in fact, happened. In the case of an omission, they are answered by reference to what would or would not have happened had the act occurred (See, for example, Duyvelshaff v. Cathcart and Ritchie Ltd.; Quigley v. Commonwealth (1981) 55 ALJR 579 ; 35 ALR 537 . See also Hart and Honore, Causation In The Law, 2nd ed. (1985), pp 59-61 where the authors identify the hypothetical nature of an enquiry as to the causal significance of providing or failing to provide a person with, or depriving a person of, an opportunity). In that exercise, the larger philosophical questions are brushed aside and the issue is approached on the basis that 'when there is a duty to take a precaution against damage occurring to others through the default of third parties or through accident, breach of the duty may be regarded as materially causing or materially contributing to that damage, should it occur, subject of course to the question whether performance of the duty would have averted the harm' (Sutherland Shire Council v. Heyman (1985) 157 CLR 424, per Mason J. at p 467. See also Hart and Honore, op.cit., p 38).