M'Naghten’s Case

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M'Naghten’s Case
Court House of Lords
Citation 0 Cl. & F. 200, 8 Eng. Rep. 718
Date decided 1843
Appealed from Old Bailey

Facts

  • Daniel M'Naghten (1813 – May 1865) wanted to assassinate the British prime minister.
  • In January 1843, M'Naghten shot & killed Edward Drummond, the prime minister's secretary.
  • Physicians found M'Naghten to be totally insane.
  • M'Naghten's acquittal caused public furor.

Procedural History

  • M'Naghten pled "not guilty" to Drummond's murder.
  • M'Naghten announced that his intention was to shoot the Prime Minister, Robert Peel.
  • The jury at the Old Bailey found M'Naghten "not guilty" on grounds of insanity.
  • The judges were called before the House of Lords to explain their reasoning.

Issues

If as a result of mental disease, the defendant didn't know or appreciate the nature or quality of the criminal act he committed, or didn't know it was wrong, can he be found not guilty by reason of insanity?

Holding

House of Lords: Yes; a defendant will be found "not guilty" by "reason of insanity" if, as a result of mental disease, he didn't know or appreciate the nature or quality of the criminal act he committed, or didn't know it was wrong.

Rule

Lord Chief Justice Tindal: Jurors should always be told to presume that a defendant is sane.

Proving insanity is the responsibility of the defendant. Medical experts may provide their scientific opinions.

Resources