Novus Actus Interveniens in UK Law

It is quite possible that in spite of all reasonable care his leg may give way in circumstances such that as a result he sustains further injury. But if the injured man acts unreasonably he cannot hold the defender liable for injury caused by his own unreasonable conduct. The chain of causation has been broken and what follows must be regarded as caused by his own conduct and not by the defender's fault or the disability caused by it.

These authorities suggest that, once liability is established, any question of the remoteness of damage is to be approached along the following lines which may, of course, be open to refinement and development.

Of course, a necessary ingredient of the crimes of murder and manslaughter is that the accused has by his act caused the victim's death. Even where it is necessary to direct the jury's minds to the question of causation, it is usually enough to direct them simply that in law the accused's act need not be the sole cause, or even the main cause, of the victim's death, it being enough that his act contributed significantly to that result.

So in all these cases the real question is, what is the damage for which the defendant under consideration should be held responsible. The nature of his duty (here, the common law duty of care) is relevant; causation, certainly, will be relevant —but it will fall to be viewed, and in truth can only be understood, in light of the answer to the question, from what kind of harm was it the defendant's duty to guard the claimant.

The rationale of the principle that a novus actus interveniens breaks the chain of causation is fairness. It is not fair to hold a tortfeasor liable, however gross his breach of duty may be, for damage caused to the claimant not by the tortfeasor's breach of duty but by some independent, supervening cause (which may or may not be tortious) for which the tortfeasor is not responsible.

Unless it can be shown, therefore, that Dr. Baker displayed such an unreasonable disregard for his own safety as to amount to negligence on his own part - with which suggestion I will presently deal - I do not think, it can be said that his set constituted a novus actue interveniens.

These cases shew that, where human action forms one of the links between the original wrongdoing of the defendant and the loss suffered by the plaintiff, that action must at least have been something very likely to happen if it is not to be regarded as novus actus interveniens breaking the chain of causation.