Gross Negligence Manslaughter

CPS guidance on homicide adopts the concise formulation given by the President of the Queen's Bench Division in Rudling [2016] EWCA Crim 741, describing the elements as "the breach of an existing duty of care which it is reasonably foreseeable gives rise to a serious and obvious risk of death" and does in fact cause death, in circumstances where, having regard to the risk of death, "the conduct of the defendant was so bad in all the circumstances as to amount to a criminal act or omission". This formulation folds together what are, in substance, four distinct questions for the jury: whether a duty of care existed, whether it was breached, whether the breach gave rise to a serious and obvious risk of death that was reasonably foreseeable, and whether the breach was so culpable as to justify criminal, rather than merely civil, liability.

The origin of that final 'criminality' threshold is the House of Lords decision in R v Adomako, which CPS guidance on corporate manslaughter causation records as having used language such as "‘so bad that it amounts to a crime and deserving of punishment’" to capture just how far short of acceptable conduct the breach must fall - guidance which cites the case by name: "see in particular R v Adomako (1994) 99 Cr App R 362". Because that threshold is deliberately left as a question of degree for the jury rather than reduced to a checklist, CPS guidance observes that in practice "the duty of the Judge is to bring home to the jury the very high threshold which amounts to gross failure" - meaning ordinary carelessness, even serious carelessness that would found civil liability in negligence, is not enough; the breach must be so extreme that a jury considers it deserving of criminal punishment.