self-defence

A defence at common law to charges of *offences against the person (including homicide) when *reasonable force is used to defend oneself, or one’s family, or anyone else against attack or threatened attack. The scope of the defence often overlaps with the statutory right to use reasonable force to prevent a crime, but also extends to cases in which the statutory right is inapplicable (for example, when the attacker is for some reason not guilty of a crime). There is no rule of law that a person must retreat before acting in self-defence. If a person acting in self-defence mistakenly uses more force than was necessary in the circumstances and kills his attacker, he has no defence of self-defence (since the force was not reasonable) and the killing will therefore amount to murder, unless he can show that there was also *provocation. However, in deciding whether the force used was justified or reasonably thought to be justified, the jury must bear in mind the difficulty of quickly assessing the correct amount of force to be used. See also *general defences.