would be possible to ask for a detailed medical evaluation at a post mortem to determine the initial degree of injury and the extent to which B's life was threatened, followed by a second set of injuries from the collision and their contribution. If the first incident merely damaged B's leg so that he could not move, it is tempting to assert that C's driving must have been the more substantial cause and so represents a novus actus breaking the chain. Equally, if B was bleeding to death and the only contribution that the driving made was to break B's arm, the driving is not a novus actus and does not break the chain. But this approach ignores the issue of A's foresight. Roads are, by their nature, used by vehicles and it is clearly foreseeable that a person left lying on the road is at risk of being further injured by an inattentive driver. Hence, if A leaves B on the road with knowledge of that risk and a foreseeable event occurs, A remains the more proximate cause. This leaves whether the test of foresight should be subjective, objective or hybrid (i.e. both subjective and objective). Obviously, there is no difficulty in holding A liable if A had actual knowledge of the likelihood that B would be further injured by a driver. The fault which caused the initial injury is compounded by the omission to move B to a safer place or call for assistance. But let us assume that A never averts the possibility of further injury. The issue is now the extent to which knowledge may be imputed objectively. The future? A difficult issue that has arisen recently is the case where the defendant neither factually causes the harm, nor increases the risk of its occurrence. In Chester v Afshar , a doctor negligently failed to warn a patient of risks inherent in an operation, specifically cauda equina syndrome. The patient had the operation and a risk materialized causing injury. It was found that even if the patient had been warned, the patient would still have undergone the operation, simply at a different time. The risk of the injury would be the same at both times. Accordingly, the doctor neither caused the injury (because but for the failure to warn, the patient would still have gone ahead with the operation), nor increased the risk of its occurrence