The claimant suffered asbestosis which is a cumulative disease. The claimant had worked with the defendant for half his working life and in similar environment in other times. It was held that the defendant is only liable for the period of the breach of duty. Despite the material contributory nature of the defendant's breach, unlike the other cases such as Bonnington, asbestosis was a 'divisible' damage as it is cumulative. It was also said that, strictly speaking, the claimant is only entitled to damages to the extent of the claimant's breach. However, if the point is never raised by the defendant, the claimant will succeed in full.
In Allen v British Rail Engineering , Holtby was applied even where it was impossible to be precise about the attribution, but the damage was nevertheless cumulative. The judge apportioned damages by reducing (1) a sum to represent damage sustained prior to the point in time at which the defendants were in breach of duty, (2) sum to represent damage sustained after the claimant ceased to be employed by the defendants (3) a sum to take account of the damage already suffered and the fact, that on the evidence the exercise of reasonable care by the defendants would only have reduced the claimant's exposure by half.
Tahir v Haringey Health Authority  The claimant alleged that the delay in operating on him due to his condition had worsened his prospect of recovery. The court held that where there has been negligence resulting in delayed medical treatment it is not sufficient for the claimant to show that there was material increase in the risk or damage. He has to go further and prove that damage was actually caused.
In the absence of findings of fact that identify or quantify the additional damage, it was not appropriate for a judge to adopt a proportionate approach by quantifying the total disability and then asking what proportion of the disability is attributable to the delay. Causation in Law 'Two causes may both be necessary precondition of a particular result – damage to X – yet the one may, if the facts justify that conclusion, be treated as the effective, and the other ignored for the purposes of legal liability (Stapely v Gypsum Mines Ltd ).
Having eliminated irrelevant factual 'causes' by the 'but for' test, the court must still decide which of the 2 or more factual causes are to be regarded as the cause in law of the claimant's damage (i. e. the cause for the purpose of attributing legal responsibility). Successive sufficient causes When 2 independent events, each of which would be sufficient to cause the harm, occur simultaneously, the practical solution is to say both caused the harm (Cook v Lewis). Performance Cars Ltd v Abraham  When 2 events are separated in time, generally, the first event should be treated as the cause.
Certainly, this is so where the tort comes the second. This case is authority for cases where the claimant or his property is damaged in some ways; the defendant is responsible only for the additional damage that he has caused. Here the defendant was held not liable for damaging the plaintiff's car which was already damaged and required re-spray. But the negligence of the defendant did not necessitate a higher cost in repairs than what it would have cost him to repair if the second accident would not have taken place. Thus, the defendant was not liable.
Carslogie Steamship Co. Ltd v Royal Norwegian Govt.  This is authority for actus novus interviniens. Even when the tort occurs first, the subsequent event may supervene, removing the causative potency of the original wrong The plaintiff's ship was damaged solely by the negligence of the defendants. It was then, to sail to the US for repairs and in its course, met a storm and suffered more damage. The collision damage and the heavy-weather damage were repaired together, taking 51 days. The collision damage alone would have taken only 10 days.
HoL held that the plaintiffs could not claim for the loss of the use of the vessel for the 10 days attributable to the defendants as the ship was in any event out of use at that time for heavy-weather damage repairs. Thus, the whole loss was attributed to the subsequent innocent cause. In Baker v Willoughby  The plaintiff's leg was injured in a road accident caused by the defendant's negligence. This affected his mobility and reduced his earning capacity. Subsequently, the plaintiff was shot in the same leg by robbers at his work place and had to amputate that leg.
The defendant argued that he should only have to compensate for the loss up to the date of the robbery. HoL disagreed and held that the defendant remained responsible for initial disability after the amputation. If the robbers had been sued, they would have been liable only for the additional loss that they had inflicted and not the whole disability. The defendant's argument would have left the plaintiff under-compensated because he would not have been compensated at all for the original injury after the robbery occurred.
It would have been clearly wrong that the plaintiff should fall between 2 tortfeasors in this way, receiving less in damages than he would have received had there been no interval between the 2 torts. Lord Reid said in the case: 'a man is not compensated for the physical injury. He is compensated for the loss he suffers as a result of that injury. His loss is not having a stiff leg, it is in his inability to enjoy the basic amenities of life that depend on the freedom of movement and his inability to earn as much as he could have earned.
The second loss did not reduce these losses, so it should not be obliterated'. In Jobling v Associated Diaries Ltd  the second successive sufficient causation was not a tort but a conditioned the plaintiff subsequently suffered. Thus the HoL apportioned the damages such that the defendants were only liable for the reduced earning of the plaintiff for the period before the intervening condition. After which the supervening disease terminated their responsibility. This result was decided not on the basis of causation but on the 'vicissitude argument'
Vicissitude argument – When assessing damages for the future loss of earning, the awarded is discounted for the possibility that other contingencies might, in any event, have reduced the claimant's earning capacity or working life. A subsequent illness is one of the 'vicissitude of life' and, applying the principle that the court will not speculate about future events when the facts are known. Heil v Rankin  Here, the claimant was involved, in the course of his employment, an even that triggered of post-traumatic stress disorder.
As a result he was unable to continue being employed. The judge reduced the claimant's award of damages on the basis that had he remained in employment and experienced another such (tortious) incident, he would have to give up work in any event. The Court of Appeal held that when assessing damages for the future loss of earnings, where there was a risk that the claimant might become the victim of a tort in the future which would have caused him to give up work, that risk would be taken into account, thereby reducing the loss of future earnings claim.
The court rejected Willoughby argument and applied the vicissitudes argument, on the ground that otherwise the claimant was likely to be over-compensated. If the claimant was to be compensated on the basis that he would have continued employment till retirement, but it was likely that future tortious acts would have caused him to give up employment, then it was 'self-evident' that he was being over-compensated. Intervening Act Sometimes, the defendant's negligence forms part of a sequence of events leading to harm to the claimant.
Where the act of another person, without which the damage would not have occurred, intervenes between the defendant's negligence and the damage, the court has to decide whether the defendant remains responsible or whether the acts constitute a novus actus intervieniens – whether the subsequent act can be regarded as breaking the causal connection between the negligence and the damage. There are 2 approaches to deciding if an event is an novus actus intervieniens:
– Causation The test asks whether the act was 'reasonable' in the circumstances (i. e. was it part of the 'ordinary cause of things' which flowed from the wrongful act). This has to be measured against the nature of the risk created by the defendant. 'Reasonable' in this context tends to relate to the voluntariness of the act. Not whether it was careless. The more voluntary the act the less reasonable it is and the more potent is its causative effect.
Careless behavior will generally be less potent causally than a voluntary act, even if the act can be called 'reasonable'. Alston v Marine Trade Insurance Co. Ltd  The plaintiff was a victim of tort created by the defendants. In hospital, he ate cheese that reacted with the medicine he took which caused a stroke. The latter event was reasonable but the consequences were unforeseeable thus, the defendants were not liable for that. The Oropesa  Here, 2 ships collided as the result of the defendant's negligence.
Despite bad weather conditions, the master of one ship sailed to the other ship to confer with the master and in the course of sailing, some crew in the lifeboat drowned. The plaintiffs (the parents of the drowned sailors) brought an action against the defendants who claimed that the master's decision to sail was an novus actus intervieniens. The court disagreed. It said to constitute novus actus intervieniens the act must be '… ultroneous, something unwarrantable, a new sequence of events, something which can be described as unreasonable or extraneous or extrinsic. '