Insanity Defence — MRCPsych Paper B MCQ
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Correct answer: C — M’Naghten’s Case (1843)
M’Naghten’s Case (1843) is correct. Following Daniel M’Naghten’s acquittal, judges gave answers to questions posed by the House of Lords; these became the M’Naghten Rules. The defence requires a defect of reason arising from a disease of the mind such that the defendant did not know the nature and quality of the act, or did not know that it was legally wrong. R v Pritchard concerns fitness to plead. R v Byrne concerns diminished responsibility. R v Windle interpreted “wrong” under the M’Naghten Rules as contrary to law but did not establish the rules. Bratty concerns automatism and the relationship between automatism and insanity.
Reference: Law Commission, Criminal Appeals Consultation Paper, paragraph 6.184 and footnote 125, 2025. https://cdn.websitebuilder.service.justice.gov.uk/uploads/sites/54/2025/02/Criminal-Appeals-Consultation-Paper-1.pdf