The burden of establishing insanity in a criminal trial is on the defence on the balance of probabilities.
Lord Diplock said: ‘I agree with what was said by Devlin J. in Reg. v. Kemp (1957) 1 QB 399, 407, that ‘mind’ in the M’Naghten Rules is used in the ordinary sense of the mental faculties of reason, memory and understanding. If the effect of a disease is to impair these faculties so severely as to have either of the consequences referred to in the latter part of the rules, it matters not whether the aetiology of the impairment is organic, as in epilepsy, or functional, or whether the impairment itself is permanent or is transient and intermittent, provided that it subsisted at the time of commission of the act. The purpose of the legislation relating to the defence of insanity, ever since its origin in 1800, has been to protect society against recurrence of the dangerous conduct. The duration of a temporary suspension of the mental faculties of reason, memory and understanding, particularly if, as in Mr. Sullivan’s case, it is recurrent, cannot on any rational ground be relevant to the application by the courts of the M’Naghten Rules, though it may be relevant to the course adopted by the Secretary of State, to whom the responsibility for how the defendant is to be dealt with passes after the return of the special verdict of ‘not guilty by reason of insanity.’ To avoid misunderstanding I ought perhaps to add that in expressing my agreement with what was said by Devlin J. in Kemp, where the disease that caused the temporary and intermittent impairment of the mental faculties was arteriosclerosis, I do not regard that learned judge as excluding the possibility of non-insane automatism (for which the proper verdict would be a verdict of ‘not guilty’) in cases where temporary impairment (not being self-induced by consuming drink or drugs) results from some external physical factor such as a blow on the head causing concussion or the administration of an anaesthetic for therapeutic purposes.’
Judges:
Lord Diplock
Citations:
[1984] AC 156, 1983] 2 All ER 673, (1983) 77 Cr App R 176, [1983] 3 WLR 123
Jurisdiction:
England and Wales
Cited by:
Cited – Regina v Antoine HL 30-Mar-2000
The appellant sought to argue that despite having been found unfit to plead under the 1964 Act, it was still open to him to argue that the defence under section 2 of the 1957 Act applied, and that he was entitled to be plead diminished . .
Cited – O’Connor, Regina (On the Application of) v HM Coroner for District of Avon and Another Admn 7-May-2009
Two children died when their father jumped with them from a hotel balcony. The father had been acquitted in Crete of manslaughter after evidence of his psychiatric condition. The applicant now challenged the English coroner’s verdict of unlawful . .
Lists of cited by and citing cases may be incomplete.
Crime
Updated: 29 April 2022; Ref: scu.182550