R v Lamb [1967]

In R v Lamb [1967] 2 QB 981; [1967] 3 WLR 888, the Court of Appeal considered the principles of constructive manslaughter, emphasising the requirement that the unlawful act must constitute a separate offence, and its corresponding mens rea must be present.

The facts of the case involved the defendant pointing a revolver at his friend and pulling the trigger as a joke, resulting in the unintended death of his friend. the defendant mistakenly believed that the bullets were not in position, and thus, the striking pin could not hit them. However, a bullet was brought into the firing position when the trigger was pulled. Expert witnesses agreed that such a mistake was commonly made.

During the trial, the judge did not instruct the jury that the mens rea for assault, which at that time was limited to intent, had to be established for a conviction of constructive manslaughter. The defendant was ultimately convicted of constructive manslaughter.

The Court of Appeal allowed the appeal, leading to the quashing of the conviction. Sacks LJ, delivering the judgment, emphasised that for a conviction of constructive manslaughter, the intent for the assault must be proven. In this case, the judge had misdirected the jury by not instructing them that the mens rea for the assault charge needed to be established.

Sacks LJ further highlighted that, due to the defendant's mistake, intent for the assault was not present. The jury should have been directed to take the defendant's mistake into account when considering the mens rea for the assault charge.

The case underscores the importance of correctly instructing the jury on the elements required for a conviction in cases of constructive manslaughter.
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