Tort; Negligence; liability for physical harm caused; acceleration of harm.
Facts: The plaintiff, a passenger in a car, suffered injuries (including a blow to the head) in an accident caused by the defendant, who was driving another car. The plaintiff subsequently suffered a brain haemorrhage and brain damage. The medical evidence suggested that although the accident probably contributed to the haemorrhage happening when it did, the haemorrhage was going to occur at some point anyway.
Issue: Was the driver liable to pay compensation for the haemorrhage suffered by the plaintiff?
Decision: The plaintiff was only entitled to damages for harm that he would not have suffered without the driver's negligence.
Reason: The driver could not be held responsible for something that would have occurred even if he had not been negligent. However, the court held that the plaintiff was entitled to damages for the period in respect of which the haemorrhage was accelerated, and for the extent to which the haemorrhage was more severe than it might otherwise have been.