The question of unfitness to plead is determined by a judge. The decision should normally be made as soon as it arises, which would ordinarily be before
arraignment, but the court may postpone consideration of unfitness until any time before the opening of the defence case. Since the 1991 Criminal Procedure (Insanity and Unfitness to Plead) Act, if the judge determines that the defendant is unfit to plead, a "
trial of the facts" is held in which evidence is heard and the jury asked to determine whether the defendant did the act or made the omission charged against them as the offence. This process avoids the detention of innocent persons in hospital merely because they are mentally unfit. It has been held that the reference to the "act or omission" means that the jury should not normally consider whether the defendant had the requisite
mens rea. If the jury find that the defendant is unfit to plead, the judge may: • make a guardianship order within the meaning of the
Mental Health Act 1983; • make a supervision and treatment order within the meaning of Schedule 2 to the
Criminal Procedure (Insanity and Unfitness to Plead) Act 1991; or • make an order for his absolute discharge. ==Criticism==