What does the insanity defence mean?
In criminal law, insanity is a defence that arises from a claim that the perpetrator was acting under the influence of an `internal’ derrangement of the mind. An `external’ derrangement may constitute Automatism. Note that insanity has been held to include epilepsy. Insanity can be raised in a jury trial or a summary trial, although the latter is unusual. Although the procedure for a plea of insanity in a trial on indictment are fixed by statute, the right to plead insanity in a summary trial remains a common law matter, so the procedures are different. In particular, a successful defence of insanity in a magistrates’ court results in an Acquital, while in a jury trial there is either a Discharge, or an order for detention in hospital or treatment (as for a claim that the accused is unfit to plead — see: InsanityAndUnfitnessToPlead). Where insanity is offered as a defence — rather than as a claim of unfitness to plead — the relevant question is whether the accused was insane at the
