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(1843) 4 St Tr NS 847; (1843) 10 Cl and Fin 200. The debate on this case in the House of lords established the Mnaghten rules on insanity. The case itself is not particular interesting: Daniel M'Naghten attempted to murder Sir Robert Peel, but failed and killed his secretary instead. His acquital lead to controversy, hence the debate and the formulation of the rules.