Acts of a third party- R v Pagett (1983): " In law [D's] act need not be the sole cause, or even the main cause, of [V's] death, it being enough that his act contributed significantly to that result."
R v Cheshire (1991): "Even though negligence in the treatment of [V] was the immediate cause of his death, the jury should not regard it as excluding the responsibility of [D] unless the negligent treatment was so independent of his acts, and itself was so potent in causing death, that they regard the contribution made by his acts as insignificant."