R v Kennedy (No 2) [2007] UKHL 38; [2008] 1 AC 269

Kennedy and Marco Bosque shared accommodation. Bosque asked Kennedy for something to help him sleep. Kennedy prepared a syringe containing heroin and handed it to Bosque, who injected himself and later died from the drug. Kennedy was convicted of supplying heroin and unlawful act manslaughter. The manslaughter case treated Kennedy's preparation and supply of the syringe as causing the death, despite Bosque's own act of injection. After earlier appeals and a reference by the Criminal Cases Review Commission, the House of Lords considered whether Kennedy had 'administered' the drug, was jointly responsible for Bosque's injection, or remained a legal cause despite the deceased's autonomous choice.

Can a drug supplier be guilty of unlawful act manslaughter where a fully informed and responsible adult freely and voluntarily injects the supplied drug and dies?

The House of Lords unanimously allowed Kennedy's appeal and quashed the manslaughter conviction. Bosque's free, deliberate and informed decision to inject himself broke the chain of causation between Kennedy's supply and the death. Kennedy had not 'administered' the drug within section 23 of the Offences Against the Person Act 1861 merely by preparing and handing over the syringe. He was not a secondary party to Bosque's self-injection because self-administration was not itself a criminal offence to which accessory liability could attach. Although supplying heroin was unlawful, that offence did not cause the death once Bosque's autonomous act intervened. The decision does not protect a supplier who directly administers the drug or where the recipient lacks relevant capacity or freedom.

Where a fully informed and responsible adult freely and voluntarily self-administers a drug, that autonomous act ordinarily breaks the chain between the supplier's conduct and the resulting death. Mere preparation and supply are not the same as administering the substance, although liability may differ if the supplier participates in administration or the choice is not free and informed.

The judgment resolved inconsistent authority on drug-supply manslaughter and reasserted personal autonomy within criminal causation. It distinguishes factual contribution from legal causation: making an injection possible is insufficient when the deceased independently chooses to perform the decisive act. The case should be contrasted with R v Pagett, where intervening conduct was not free and independent, and with medical-treatment cases such as R v Cheshire. It also confines unlawful act manslaughter because the prosecution must prove that the defendant's own unlawful act caused death, not merely that unlawful conduct preceded it.