D shot and killed V while insane and the HL had to answer whether insanity was a defence. They said that it was: LCJ Tindall said “to establish a defence on the ground of insanity, it must be clearly proved that, at the time of the committing of the act, the party accused as labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or, if he did know it, that he did not know he was doing what was wrong.” The question is to be left to the jury and the burden of evidence is on the defence. Also, where D is insane so as to misunderstand the circumstances but is otherwise fine, the court will judge him according to the circumstances as he believed them to be e.g. if D insanely believes that V is trying to kill him and D kills V in self-defence he is not liable. If D insanely believes that V has insulted him and therefore kills him, then he is liable. NB dissenting, Maule said that such a defence couldn’t be created without parliament’s approval.