3. Causation

Causation is part of the actus reus of a result crime. The question in homicide is whether the accused's act caused the death. If death came from another cause, the result crime is not committed. White is that case again. The mother died of heart failure. The poison was not a cause.

The prosecution must prove two things beyond reasonable doubt. But for the accused's conduct, the victim would not have died as and when he did. And the original injury was more than a minimal cause. Killing includes accelerating death, but the acceleration must be more than trivial. That is the de minimis rule. A cause in fact is not always a cause in law. The conduct must be an operating and substantial cause. The printed phrase is sometimes "coma sine qua non". The idea is sine qua non: a but-for cause. A but-for cause is not enough on its own.

Medical treatment. In R v Jordan the stab wound was overtaken by the mistaken administration of antibiotics, and the conviction was quashed. That was a new intervening act. In R v Smith the treatment was thoroughly bad, and a comrade dropped the wounded man twice on the way to the station. The conviction stood. Lord Parker said that if at death the original wound is still an operating and substantial cause, death results from the wound even though another cause is operating. Only if the wound is merely the setting in which another cause operates, or the second cause is so overwhelming that the wound is merely part of the history, does the chain break. Switching off a life-support machine after brain-stem death does not relieve the accused. Malcherek and Steele were both convicted of murder. Whether the doctors were also a cause was immaterial. They were not on trial.

The victim's own act. In R v Roberts a passenger jumped from a moving car to escape sexual advances. Causation of her injuries was established. Blaue is the thin-skull rule, and it covers the whole person, not only the body. Blaue stabbed a young woman and pierced a lung. She refused a blood transfusion because she was a Jehovah's Witness, and she died. Lawton LJ said those who use violence must take their victims as they find them. It does not lie in the assailant's mouth to say the belief was unreasonable. The question is what caused the death. The answer is the stab wound. Hayward is the physical version. He chased his wife into the street. She had a thyroid condition. She died from the combination of fright, emotion and exertion. He took her as he found her.

A new act of a third person breaks the chain only when it becomes the operative cause and pushes the accused's conduct into history. Smith and Malcherek were not that case. Jordan was. Contributory negligence by the victim does not, of itself, break the chain. In Swindall and Osborne it was immaterial that the man who was run down was deaf, or drunk, or negligent.

If causation fails, the accused is acquitted of the result crime. Liability can remain for the original non-fatal offence, such as wounding.