R v Kennedy (No 2)  UKHL 38
CAUSATION - NOVUS ACTUS INTERVENIENS - UNLAWFUL ACT MANSLAUGHTER
The defendant and victim were living together in a hostel. The victim visited the defendants room and asked for “a bit to make him sleep”. The defendant prepared a dose of heroin for the victim, then passed him the syringe so that he could self inject. The victim did so, and died several hours later as a result of choking on his own vomit while under the influence of the drug. The defendant was convicted of unlawful act manslaughter and appealed.
The key question before the House of Lords was whether the victim’s act in self injecting was an intervening act such as to break the chain of causation. An additional question was which unlawful act the manslaughter conviction should properly have been based.
It was held that as the victim was a fully informed and consenting adult, who had freely and voluntarily self-administered the drug without any pressure from the defendant, this was an intervening act. The chain of causation between the defendant’s act in supplying the drug and the victim’s death was therefore incomplete. The reasoning of the House was based on the need for the criminal law to respect free will and to treat the victim, being an adult of sound mind, as an autonomous individual. The defendant’s conviction was therefore overturned.
On the question as to which unlawful act the manslaughter conviction was founded, the House held in a case where there were several legitimate and valid alternative formulations, it was of little consequence how the act was identified. The essential point was that the chosen formulation should be clear and applied consistently throughout the trial.