## Facts

- The defendant, Mr. Kennedy, prepared a syringe containing heroin and handed it to the victim, Mr. Marco Bosque.
- Mr. Bosque subsequently injected himself with the heroin and died from an overdose.
- Kennedy was initially convicted of manslaughter on the basis that his preparation and provision of the syringe contributed to Bosque's death.
- The prosecution did not claim that Kennedy had physically injected Bosque, but argued that his assistance constituted an unlawful act leading to manslaughter.
- The case proceeded to the House of Lords, focusing on whether Bosque's act of self-injection broke the chain of causation regarding Kennedy’s criminal liability.

## Issues

1. Whether the voluntary and informed self-injection of heroin by the victim constituted a novus actus interveniens, thereby breaking the chain of causation between Kennedy’s actions and the victim’s death.
2. Whether the mere act of unlawfully supplying drugs imposes liability for manslaughter when the victim exercises autonomous choice in self-administration.
3. Whether criminal causation in cases of drug-related deaths should distinguish between supply and direct administration of drugs.

## Decision

- The House of Lords held that an adult victim's voluntary and informed act of self-injecting drugs constitutes a novus actus interveniens, breaking the chain of causation from the person who supplied the drug.
- Kennedy’s liability for manslaughter did not arise, as the law assumes adults of sound mind act with free will and are responsible for their own decisions.
- The court distinguished liability in cases where the defendant directly administers the drug, in which cases causation may remain unbroken.
- The judgment clarified that supply alone does not equal criminal responsibility for the resulting death if the victim knowingly and freely self-administers the drug.

## Legal Principles

- Novus actus interveniens: A new, intervening act by a competent adult can break the chain of causation in criminal liability.
- Individual autonomy and free will are fundamental to assessing criminal responsibility, especially in unlawful act manslaughter.
- The law distinguishes between the supply of drugs and their administration; voluntary self-injection by the victim precludes manslaughter liability for the supplier.
- In drug-related manslaughter, criminal liability may arise only where the defendant administers the drug to the victim, not where the victim self-administers in a voluntary and informed manner.

## Conclusion

R v Kennedy established that a competent adult’s voluntary and informed choice to self-inject drugs interrupts the legal chain of causation, absolving the supplier of manslaughter liability; this decision highlights the centrality of individual autonomy in criminal law and provides clear guidance for future cases involving unlawful act manslaughter and drug supply.


R v Kennedy [2007] UKHL 38