Court case[1935] 1 KB 146

The defendants' servant left a two-horse van unattended in a crowded street. A boy threw a stone at the horses and they bolted down the street. A police constable on duty inside a police station nearby saw that a woman and several children were in grave danger in the path of the horses. He ran out, seized the horses and managed to stop them, but was seriously injured in doing so. He sued the defendants for negligence. The defendants pleaded that he had voluntarily run the risk and that the boy's mischief was the cause of the accident.

The Court of Appeal held the defendants liable. Leaving horses unattended in a busy street was negligent, and the very kind of thing likely to happen (that someone would startle them) did happen; the boy's act did not break the chain of causation. The maxim volenti non fit injuria did not apply to the constable: he acted under a legal and moral duty to protect persons in danger, in an emergency created by the defendants' negligence; his act was not a free and voluntary acceptance of the risk but the natural and foreseeable response of a brave man. Greer LJ said that the defence does not apply where the plaintiff, under an exigency caused by the defendant's wrongful misconduct, consciously and deliberately faced a risk, even of death, to rescue another from imminent danger.