Causation (Legal)

Factual causation asks a counterfactual question: would the harm have occurred without the defendant's conduct? CPS legal guidance on corporate manslaughter applies this in directing that, in cases of failure by omission, “The prosecution must prove that, but for the alleged gross breach of duty, the deceased would have survived”, or would not have died at that time or in those circumstances. If the same outcome would have followed regardless of the breach, causation is not established on the facts.

Legal causation goes further, asking whether the defendant's conduct remains a sufficiently operative cause of the outcome notwithstanding events occurring afterwards, including the actions of the victim or a third party. CPS guidance on homicide illustrates this with the example of suicide following an earlier unlawful act: “Suicide will not necessarily break the chain of causation but the psychiatric injury caused by D's acts must have been an operating and significant cause” of death. An intervening event does not automatically sever the chain of causation — the question in each case is whether the defendant's conduct remained an operating and significant cause of the eventual result.