The Anglo-Thai Peace Treaty (long title: Formal Agreement for the Termination of the State of War between Siam and Great Britain and India) signed in Singapore on 1 January 1946 ended the state of war that had existed between Thailand and the United Kingdom since the former's declaration of war of 25 January 1942 during World War II. Although the Thais had also declared war on the United States on the same day, a U.S.–Thai peace treaty was never signed because the American government opted not to recognise the legality of the declaration in light of the Japanese invasion of Thailand on 8 December 1941.