The Left Fraction, sometimes calling itself the Left Fraction, British Section of the Fourth International (In Opposition), was a Trotskyist organisation in the United Kingdom. The group formed as a tendency of the Revolutionary Socialist League (RSL) in 1940. It was described by other tendencies in the disintegrating organisation as pacifist. The group opposed Trotsky's Proletarian Military Policy, and was expelled in 1943. On the first day of conference held by the Fourth International in 1944, the Left Fraction and also the Trotskyist Opposition were reunited with the RSL. Despite the objections of the Left Fraction, the second day saw the reformed RSL unified with the rival Workers International League – on the WIL's terms – to form the new Revolutionary Communist Party (RCP).