HMS Duncan was a D-class destroyer leader built for the Royal Navy in the early 1930s. The ship was initially assigned to the Mediterranean Fleet before she was transferred to the China Station in early 1935 where she remained until mid-1939. Duncan returned to the Mediterranean Fleet just after World War II began in September 1939. She was transferred to the Home Fleet in December 1939, although she was badly damaged in a collision the following month, and required repairs that lasted until July 1940. The ship joined Force H at Gibraltar in October, escorting the larger ships and various convoys until March 1941 when she was transferred to West Africa for convoy escort duties for a few months. Duncan rejoined the 13th Destroyer Flotilla at Gibraltar in July and escorted several convoys to