M'naghten's Case

10 Cl. & F. 200, 8 Eng. Rep. 718 (1843)


M'Naghten (D) was indicted for the murder of Edward Drummond. D was a woodcutter who assassinated Edward in the mistaken belief that Edward was the Prime Minister, Sir Robert Peel. D labored under the delusion that Prime Minister was responsible for all his misfortune in life. Upon arrest, D made an allegation that the Tories in his city follow him and persecute him wherever he goes and that they have entirely destroyed his mind such that they wish to murder him. D pled not guilty to the charge of murdering Edward. At D's trial, there was extensive expert testimony that D was obsessed with delusions and suffered from acute insanity. It was determined that D could not distinguish right from wrong nor control the import of his delusions. Lord Tindal was so convinced of D’s insanity that despite wanting to take the matter from the jury he gave an instruction for insanity to the jury and D was found not guilty by reason of insanity. That instruction was based on the ability of D to determine right from wrong. A public outcry ensued and a number of judges were invited to attend the House of Lords for the purpose of delivering answers to certain questions propounded to them.