A leading authority on causation in criminal law, establishing the “thin skull rule” applies to both physical and moral characteristics. A defendant must take the victim as they find them, including their religious beliefs. A victim’s refusal of medical treatment, even if unreasonable by ordinary standards, does not break the chain of causation. The decision sharply distinguishes criminal causation from tort mitigation principles. 

The defendant stabbed an 18-year-old woman four times, one wound piercing her lung. In hospital, doctors advised that a blood transfusion was necessary to save her life. She refused because she was a Jehovah’s Witness and signed a certificate declining transfusion even after being warned she would die. She subsequently died from bleeding into the pleural cavity.

At trial the defendant was acquitted of murder but convicted of manslaughter due to diminished responsibility. He appealed, arguing that her refusal of medical treatment constituted a novus actus interveniens.

Whether the victim’s refusal of a life-saving blood transfusion on religious grounds broke the chain of causation between the stabbing and her death. 

Appeal dismissed. The stab wound remained an operative and substantial cause of death. The refusal of treatment did not break the causal chain. The conviction for manslaughter was upheld. 

• The criminal law requires offenders to “take their victims as they find them”. This includes their physical condition and also their moral, psychological and religious characteristics.

• A victim is under no legal duty to mitigate harm by accepting medical treatment.

• Refusal of medical treatment, even if objectively unreasonable, cannot be treated as a new intervening act that relieves the defendant of liability.

• The relevant question is whether the original wound was still an operative and substantial cause of death. Here it plainly was: the physical cause of death was bleeding from the stab wound.

• Only if the subsequent act is so overwhelming that the original wound becomes merely part of the history of events (as in Jordan) will the chain be broken.