HMS Forester was one of nine F-class destroyers built for the Royal Navy during the early 1930s. Although assigned to the Home Fleet upon completion, the ship was attached to the Mediterranean Fleet in 1935–36 during the Abyssinia Crisis. A few weeks after the start of World War II in September 1939, she helped to sink one German submarine and then participated in the Second Battle of Narvik during the Norwegian Campaign of 1940. Forester was sent to Gibraltar in mid-1940 and formed part of Force H where she participated in the attack on the Vichy French ships at Mers-el-Kébir and the Battle of Dakar between escorting the aircraft carriers of Force H as they flew off aircraft for Malta and covering convoys resupplying and reinforcing the island until late 1941. During this time the ship helped to sink another German submarine.

The E and F-class destroyers were a group of 18 destroyers built for the Royal Navy during the 1930s. The ships were initially assigned to the Home Fleet, although they reinforced the Mediterranean Fleet during the Italian invasion of Abyssinia of 1935–36 and enforced the Non-Intervention Agreement during the Spanish Civil War of 1936–1939. After the beginning of the Second World War in August 1939, the E-class ships were mostly assigned to escort duties under the Western Approaches Command, while the Fs were assigned to escort the ships of the Home Fleet. Between them they sank four German submarines through March 1940 while losing only one ship to a submarine.