P walked into the middle of the road and D, driving, ran into him, causing damage to P’s leg. They both saw each other over 200 yds and neither took evasive action. The fault was ruled to be 25% P’s and 75% D’s. Shortly after the accident P was shot in the leg and it had to be amputated immediately. HL held that the subsequent shooting was irrelevant to the amount of damages that D had to pay, and that D would have to pay the value of 25% of the damage to the leg overall (i.e. NO reduction despite the fact that D did not cause the leg to be shot and amputated). The shooting and car accident were to be treated as concurrent causes of the disability and each was liable for the full damage to the leg i.e. that D should have to pay the full amount for the long term damage he would have caused (had there been no shooting) despite the fact that P would have been shot anyway (and P’s actions made irrelevant).
Lord Pearson: we should take a “unitary and comprehensive” view of the original injury, assessing it as a “devaluation” in the leg, for which the responsible party should pay (though only for the proportion of the devaluation for which he was responsible). The only thing that could change the amount to be paid is a reduction in the extent of the devaluation e.g. an unexpected recovery OR a shortening of P’s life expectancy i.e. the period over which the plaintiff will suffer from the devaluation. If another tort occurs then the new tortfeasor will be liable for the further devaluation. The life-shortening point is supported by the fact that if an injury costs P 20 years working income by destroying his capacity to work, and then after only 1 year P dies of an unrelated event, it would be unfair to make D pay for 20 years since this would no longer be compensation.
Lord Reid: There were 2 concurrent causes of P’s disability and both tortfeasors should have to pay for the suffering they cause. This seems logical: The “but for” test would support Lord Reid’s conclusion since even “but for the shooting” P would still be disabled. The correct approach is that adopted: to say that each party has to pay for the “devaluation” that they cause, making a qualification for cases where the extent of the devaluation has been reduced by something, for example a wonder-cure: this qualification is made by Lord Pearson. The shooting does not absolve P of responsibility for disabling D, since even without the shooting D would still have been disabled: it merely aggravated the situation.