The Treason Act 1842 (5 & 6 Vict. c.51) is an Act of the Parliament of the United Kingdom of Great Britain and Ireland. It was passed early in the reign of Queen Victoria. The last person to be convicted under the Act was Marcus Sarjeant in 1981, and the last person to be charged was Jaswant Singh Chail, on 2 August 2022, for trial later.