R v White [1910] 2 KB 124

White put cyanide into a drink intended for his mother because he wanted to kill her and obtain an inheritance. She was later found dead, and the poisoned drink was nearby. Medical evidence established that she had died from heart failure rather than cyanide poisoning, and no cyanide was detected in her body. The prosecution charged White with murder. Although his conduct plainly demonstrated an intention to kill and went beyond mere preparation, the poison had not made any factual contribution to the death. The trial raised the difference between possessing the mens rea for a completed offence and proving that the defendant's act caused the prohibited result. White was not liable for murder but was convicted of attempting to murder his mother.

Could White be convicted of murder when his mother would have died at the same time from an independent heart attack even if he had not poisoned the drink?

The Court of Criminal Appeal held that murder was not established because factual causation was absent. Applying what is now called the but-for test, the court asked whether the victim would have died when she did but for White's conduct. The medical evidence showed that she would: the poison had not caused or accelerated the fatal heart failure. Intention alone could not turn an independently caused death into murder. White's conduct did, however, amount to attempted murder because, intending to kill, he had carried out acts directed towards that result. The fact that the poison did not cause her death did not erase the criminal attempt represented by administering it.

Factual causation requires proof that, but for the defendant's conduct, the prohibited result would not have occurred when it did. If the result would have happened independently in the same way and at the same time, the defendant did not factually cause it, however blameworthy the intention.

White is the conventional starting point for causation questions. But-for causation is necessary in ordinary result crimes but is not always sufficient; legal causation also requires a more than minimal operating contribution and may be affected by an intervening cause. R v Smith and R v Cheshire address continuing and substantial causes, while R v Kennedy (No 2) considers free and informed intervention. The attempt conviction also reminds students to analyse possible inchoate liability when the intended completed offence fails for reasons outside the defendant's control. The case predates the Criminal Attempts Act 1981, under which modern attempt liability is assessed.