The distinction between insanity, automatism and diminished responsibility in the Laws of England and Wales. Covers the M'Naghten rule which is also a dominant rule in US legal doctrine.

"The defendant who seeks to avoid criminal liability on the basis that s/he was suffering from a mental disorder at the time of the alleged crime must have a defence that falls within one of the following, legally recognised, categories: Insanity, Diminished Responsibility or Automatism. While, at one level or another, these "mental disorder defences" share common characteristics, they each differ significantly. Unfortunately, this point does not appear to be fully appreciated in English …

…Insanity – Sleepwalking and Statutory Reform C.L.J. 1991, 50(3), 386-388 Cases 1. Alphacell [1972] 2 All ER 475 2. Burgess [1991] 2 W.L.R. 106 C.O.A. (Criminal Division) 3. Byrne [1960] 3 All ER 1 4. Cooper v. McKenna [1960] Q.L.R 406 5. Hennessy (1989) 89 Cr.App.R 10, CA 6. Kemp [1956] 3 All ER 249; [1957] 1 Q.B.399 7. M'Naghten's Case (1843) 10 C & F, 200, 8 Eng. Rep. 718. 8. Quick and Paddison [1973] Q.B. 910 9. Seers [1985] Crim.L.R, 315 10. Sullivan [1984] A.C. 156 (House of Lords) 11. Tandy [1988] Crim.L.R 308 12. Tolson (1889) Legislation 1. Homicide Act. 1957. 2. Trial of Lunatics Act 1883