was fitted the following year. Two quadruple Vickers .50-calibre (12.7 mm) Mark III machine guns were added in 1934. In July 1936, Cornwall returned home to begin a major refit, which included a Krupp cemented armour belt abreast the engine and boiler rooms as well as the dynamo room and the fire control transmitting station. This belt extended down from the lower deck. Four inches of armour were also added to protect the sides of the boiler room fan compartments. A hangar for her aircraft was added and a new, more powerful catapult was installed. The ship's director was moved to the roof of the hangar and a new power-operated director-control tower was installed in its original location. Her single four-inch AA guns were replaced with twin-gun mounts for Mark XVI guns of the same calibre. Two octuple-barrel 2-pounder mounts were added abreast the searchlight tower and the original 2-pounder guns were removed. The changes raised the ship's displacement by and cost an estimated £215,000. After the refit was completed in December 1937, the ship was assigned to the 2nd Cruiser Squadron before rejoining the 5th CS in 1939. On 5 October 1939, a month after the start of World War II, she was assigned to Force I to hunt for German commerce raiders in the Indian Ocean and spent most of the rest of the year there. Cornwall was then transferred to the South Atlantic for convoy escort duties. On 13 September 1940, the ship rendezvoused with a convoy that was carrying troops intended to capture Dakar from the Vichy French, but was detached to intercept the Vichy French light cruiser that was escorting an oil tanker to Libreville, French Equatorial Africa, five days later and forced them to return to Casablanca in French Morocco. She then returned to the Indian Ocean and sank the German commerce raider on 8 May 1941. Cornwall rescued 3 officers, 57 ratings and 22 prisoners after the battle. After the start of the Pacific War on 7 December, the ship began escorting convoys across the Indian Ocean, examples being Convoy JS.1 from Colombo, Ceylon, to the Dutch East Indies in late January–early February 1942 and the troop Convoy MS. 5 to Australia in early March. Later that month, she was assigned to the fast Force A of the Eastern Fleet. On 2 April, Cornwall and her half sister, , were detached from the