Manslaughter by an Unlawful and Dangerous Act

Manslaughter by an Unlawful and Dangerous Act

"Manslaughter by an unlawful and dangerous act" is a form of involuntary manslaughter. Its distinguishing feature is that the offender has no intention to kill or to cause grievous bodily harm, but, in the course of carrying out an act that is both unlawful and dangerous, accidentally causes the death of another. 

The Unlawful Act 

As to whether an act is unlawful, the authorities show that the unlawful act must itself be a criminal offence. A mere civil wrong (such as ordinary civil negligence) is not sufficient.  

A criminal intent (mens rea) is required, but only the mens rea of the unlawful act itself (R v Lamb [1967] 2 QB 981; R v Lowe [1973] QB 702). In one English case (R v Lamb [1967] 2 QB 981), the defendant, as a joke, pointed a loaded revolver at his friend. He had no intention of harming or frightening his friend, and both of them believed that pulling the trigger would be harmless. The defendant nevertheless pulled the trigger and shot his friend dead. Because there was no mens rea of assault, there was no "unlawful act", and manslaughter was not made out. 

In this category of manslaughter, all that is required is that the defendant had the criminal intent corresponding to the "unlawful act" itself—for example, the intention to commit an assault—and not any intention to cause death or serious injury. Even if the defendant was intoxicated or under the influence of drugs at the time of the offence, and therefore lacked clear awareness, this does not affect liability, because manslaughter is a "crime of basic intent" (that is, it requires only the intention to do the unlawful act, and no further purpose).

In an English case, the defendant, having taken LSD, suffered hallucinations, stuffed a bedsheet into his companion's mouth and beat her, ultimately causing her death. Although the defendant was not aware of what he was doing, and had no intention to kill or to cause serious injury, the court nevertheless found him guilty of manslaughter, on the basis that the unlawful act consisted of the battery of the victim, and that this assault was in itself sufficient to constitute the mens rea for manslaughter. 

The Dangerous Act 

As to whether the act is dangerous, the prosecution need not prove that the defendant knew the act to be unlawful or dangerous. For manslaughter to be made out, the unlawful act must be such that all sober and reasonable people would recognise that it would subject another person to at least some risk of harm, even if not serious harm. Where the unlawful act is not in itself a violent or dangerous offence, it remains necessary to consider whether the circumstances in which it took place exposed another person to some risk of harm. 

For example, A deliberately throws a stone at the window of a dwelling in the middle of the night, intending to cause criminal damage to property. A does not intend to hurt anyone, and it does not occur to him that anyone inside might be injured. At that moment, however, B is standing by the window; the stone shatters the glass, the fragments scatter, and B is cut and later dies from complications of the injury. The court will apply an objective standard: would a "sober and reasonable person", seeing A throw a stone at the window of a dwelling at night, consider that this conduct exposed another to at least some risk of bodily harm? The answer is very likely yes. The fact that A himself did not foresee the danger does not affect the establishment of this element.