An explanation of constructive/unlawful act manslaughter and how liability is established
How is the criminal offence of constructive manslaughter/unlawful act manslaughter established
Constructive manslaughter is a partial defence to a committal of murder, reducing the offence to manslaughter (Child and Ormerod, 2015). It is considered a ‘catch-all’ offence for defendants who kill an individual but lack the sufficient Mens Rea for murder (Law Commission, 2006).
The defence has three elements. First, there must be an unlawful act, which would be the offence the defendant would have been liable for but for the death of the victim, this is restricted to criminal offences, for example, burglary (Kennedy (No 2); R v Watson).
Second, the act must be objectively dangerous to the victim, yet need not be directed at them (Child and Ormerod, 2015). The test from R v Church is whether all sober and reasonable individuals would recognise the act would subject the victim to at least some harm. This is an objective test; the defendant need not see any risk.
Finally, the act must cause the victim’s death. Factual and legal causation need to be established. Factual causation is proven if ‘but for’ the defendant’s act, the victim would have survived (White). Legal causation is proven if the act was a proximate, substantial and operating cause of death. (Child and Ormerod, 2015)
Child, J and Ormerod, D., (2015) Smith and Hogan’s Essentials of Criminal Law. Oxford University Press
Law Commission, Murder, Manslaughter and Infanticide (Law Com No 304, 2006) Para 2.9
Kennedy (No 2)  UKHL 38
R v Watson  Crim LR 730
R v Church  1 QB 59
R v White  2 KB 124