“…there may be some room for argument about whether the approach adopted by the Tribunal was correct in principle. Conventionally, a claimant is entitled to recover damages on a 100% basis where the tortfeasor’s act has made a material contribution to his suffering the injury in question, even though there may have been other (or even more) material contributory causes. On that basis, the fact that a victim has a pre‑existing vulnerability to injury, or that the injury was only part of a complex of causes, is no ground – as such – for reducing his or her damages. That is not to say that it is wholly irrelevant. To the extent that the court concludes that by reason of that vulnerability the injury in question might well have occurred in any event, that factor would be reflected in the overall quantification of damages: that may produce a similar result to what would have been achieved by an apportionment of causation, but the reasoning is different and it will certainly not always do so. These principles have been applied in cases of psychiatric injury in such cases such as Page v Smith (No 2)[1996] 1 WLR 855 and Vernon v Bosley (No 1)[1997] 1 All ER 577 . However, the law as regards material contribution and apportionment of causation has recently been considered again by the Court of Appeal in Holtby v Brigham and Cowan (Hull) Ltd[2000] 3 All ER 420 (and see now, decided since the argument in this case, Allen v British Rail Engineering Ltd[2001] EWCA Civ 242 ); and the conventional view summarised above may be in doubt. Neither party, understandably, was anxious on this appeal to enter these treacherous waters.”
“(ii) There can be cases where the state of the evidence is such that it is just to recognise each of two separate tortfeasors as having caused the whole of the damage of which the claimant complains; for instance where a passenger is killed as the result of a head‑on collision between two cars each of which was negligibly driven and in one of which he was sitting. (iii) However, in principle the amount of the employer’s liability will be limited to the extent of the contribution which his tortious conduct made to the employee’s disability. (iv) The court must do the best it can on the evidence to make the apportionment and should not be astute to deny the claimant relief on the basis that he cannot establish with demonstrable accuracy precisely what proportion of his injury is attributable to the defendant’s tortious conduct.”
“The application of those propositions should lead to a just and principled result. We mention by way of coda that this approach seems to accord with the view of the authors of the American Law Institute Restatement of the Law, Torts , 2d (1965), section 433A(e): ‘Apportionment may also be made where a part of the harm caused would clearly have resulted from the innocent conduct of the defendant himself, and the extent of the harm has been aggravated by his tortious conduct.’”
“He [the claimant] will be entitled to succeed if he can prove that the defendant’s tortious conduct made a material contribution to his disability. But strictly speaking the defendant is liable only to the extent of that contribution. However, if the point is never raised or argued by the defendant, the claimant will succeed in full as in Bonnington Castings Ltd v Wardlaw[1956] AC 613 and McGhee v National Coal Board[1973] 1 WLR 1 .”
“36. Many stress‑related illnesses are likely to have a complex aetiology with several different causes. In principle a wrongdoer should pay only for that proportion of the harm suffered for which he by his wrongdoing is responsible […] The Thompson and Holtby cases concerned respectively deafness and asbestosis developed over a long period of exposure; not only were different employers involved but in Thompson some of the exposure by the same employer was tortious and some was not. Apportionment was possible because the deterioration over particular periods of time could be measured, albeit in a somewhat rough and ready fashion. 37. It is different if the harm is truly indivisible : a tortfeasor who has made a material contribution is liable for the whole, although he may be able to seek contribution from other joint or concurrent tortfeasors who have also contributed to the injury. In the Rahman case[2001] QB 351 , 361, para 17, Laws LJ quoted the following illuminating discussion from Prosser & Keeton on Torts , 5th ed (1984), pp 345‑346: “If two defendants, struggling for a single gun, succeed in shooting the plaintiff, there is no reasonable basis for dividing the injury between them, and each will be liable for all of it. If they shoot the plaintiff independently, with separate guns, and the plaintiff dies from the effect of both wounds, there can still be no division, for death cannot be divided or apportioned except by an arbitrary rule … If they merely inflict separate wounds, and the plaintiff survives, a basis for division exists, because it is possible to regard the two wounds as separate injuries … There will be obvious difficulties of proof as to the apportionment of certain elements of damages, such as physical and mental suffering and medical expenses, but such difficulties are not insuperable, and it is better to attempt some rough division than to hold one defendant [liable] for the wound inflicted by the other. Upon the same basis, if two defendants each pollute a stream with oil, in some instances it may be possible to say that each has interfered to a separate extent with the plaintiff’s rights in the water, and to make some division of the damages. It is not possible if the oil is ignited, and burns the plaintiff’s barn.”
“Hence if it is established that the constellation of symptoms suffered by the claimant stems from a number of different extrinsic causes then in our view a sensible attempt should be made to apportion liability accordingly. There is no reason to distinguish these conditions from the chronological development of industrial diseases or disabilities. The analogy with the polluted stream is closer than the analogy with the single fire. Nor is there anything in Bonnington Castings Ltd v Wardlaw[1956] AC 613 or McGhee v National Coal Board[1973] 1 WLR 1 requiring a different approach.”
“I respectfully wish ( obiter ) to express my doubts as to the correctness of Hale LJ’s approach to apportionment. My provisional view (given without the benefit of argument) is that, in a case which has had to be decided on the basis that the tort has made a material contribution but it is not scientifically possible to say how much that contribution is (apart from the assessment that it was more than de minimis ) and where the injury to which that has [led] is indivisible, it will be inappropriate simply to apportion the damages across the board. It may well be appropriate to bear in mind that the Claimant was psychiatrically vulnerable and might have suffered a breakdown at some time in the future even without the tort. There may then be a reduction in some heads of damage for future risks of non‑tortious loss. But my provisional view is that there should not be any rule that the judge should apportion the damages across the board merely because one non‑tortious cause has been in play.”
“While the obiter dicta of Hale LJ in Hatton are, as always, entitled to the greatest respect, the stare decisis principle requires courts of first instance, at least for the present, to take their cue in this regard from Bailey .”
“As I have said, there was in this case an inescapable issue of causation first to be resolved. But if the plaintiff had proved on a balance of probabilities that the authority’s negligent failure to diagnose and treat his injury promptly had materially contributed to the development of avascular necrosis, I know of no principle of English law which would have entitled the authority to a discount from the full measure of damage to reflect the chance that, even given prompt treatment, avascular necrosis might well still have developed. The decisions of this House in Bonnington Castings Ltd v Wardlaw[1956] AC 613 and McGhee v National Coal Board[1973] 1 WLR 1 give no support to such a view.”
“If we know – and we do know, for by the end of the case it was no longer seriously in dispute that a substantial part of the impairment took place before the defendants were in breach, why, in fairness, should they have been made to pay for it? The fact that precise quantification is impossible should not alter the position. The whole exercise of assessing damages is shot through with imprecision … I see no reason why the present impossibility of making a precise apportionment of impairment and disability in terms of time, should in justice lead to the result that the defendants are adjudged liable to pay in full, when it is known that only part of the damage was their fault. What justice does demand, to my mind, is that the court should make the best estimate which it can, in the light of the evidence, making the fullest allowances in favour of the plaintiffs for the uncertainties known to be involved in any apportionment.”
“In the absence of other stressors, which I cannot find evidence for, the cause of the above injury, [i.e. the nature of the condition which constituted her psychiatric ill-health], is the perception of treatment at work.”
“For the avoidance of doubt I have not been able to elicit any events outside of the work environment which would have materially contributed to her mental illness.”
“We did not hear any oral evidence from Dr Wise. This was unfortunate because we detected inconsistencies in the medical evidence, in particular between the first report of Dr Wise, which was prepared for the disability discrimination claim, and the second report we have just referred to. The first report is dated26 September 2008 . It refers to medical records or GP records which Dr Wise appears to have only from January 2006. The medical records that have been disclosed to us go back before that, and [show Miss Thaine] was diagnosed with [an] obsessive compulsive disorder in November 2003, and with a depressive order secondary to that in 2004.”
“We have also seen a letter from [Miss Thaine’s] therapist, Ms Florence Ekiko, who saw [Miss Thaine] in about April 2009. Ms Ekiko refers to [Miss Thaine] being referred for symptoms of depression and anxiety which she had experienced since 2004, and refers to a background of mild [obsessive-compulsive disorder.] [Miss Thaine] told Ms Ekiko, however, that she had actually felt depressed since 2006, which of course is the year that she began with her employment with the [LSE]. We wonder, in the light of what [Miss Thaine] said to Ms Ekiko, and the fact that Dr Wise appears only to have medical records from 2007, whether [Miss Thaine] has actually deliberately suppressed evidence relating to her mental state before 2006. We note in particular that [Miss Thaine] did not disclose the earlier medical records, it would appear, including Ms Ekiko’s letter, until the Friday before the hearing. There was an issue as to whether Dr Wise needed to revisit the case, in the light of the recently disclosed records, and indeed further records that [Miss Thaine’s] mother went to get on the morning of the hearing.”
“The test is not whether these employers could reasonably have foreseen that a burn would cause cancer and that he would die. The question is whether these employers could reasonably foresee the type of injury he suffered, namely, the burn. What, in the particular case, is the amount of damage which he suffers as a result of that burn depends upon the characteristics and constitution of the victim.”