HMS Porpoise (N14) was one of the six-ship class of Grampus-class mine-laying submarines of the Royal Navy. She was built at Vickers Armstrong, Barrow and launched 30 August 1932. She served in World War II in most of the naval theatres of the war, in home waters, the Mediterranean and the Far East. She was sunk with all hands by Japanese aircraft on 19 January 1945, and was the last Royal Navy submarine to be lost to enemy action.