HMS Cornwall, pennant number 56, was a County-class heavy cruiser of the Kent sub-class built for the Royal Navy in the mid-1920s.

Cornwall carried a maximum of 3,425 long tons (3,480 t) of fuel oil that gave her a range of 13,300 nautical miles (24,600 km; 15,300 mi) at 12 knots (22 km/h; 14 mph).

Her secondary armament consisted of four QF 4-inch (102 mm) Mk V anti-aircraft (AA) guns in single mounts.

Completed on 6 December 1927, she was assigned to the 5th Cruiser Squadron (CS) on the China Station and spent the bulk of the interbellum period there.

[8] 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.

[11] On 2 April, Cornwall and her half sister, Dorsetshire, were detached from the fleet, Dorsetshire to resume an interrupted refit and Cornwall to escort convoy SU-4 (composed of the U.S. Army transport USAT Willard A. Holbrook and Australian transport MV Duntroon) to Australia and the aircraft carrier Hermes to Trincomalee in Ceylon for repairs.

On 4 April, the Japanese fleet was spotted and the two cruisers left harbour and, after a hurried refuelling at sea, set out for Addu Atoll shortly after midnight.

[12] As part of the engagement known as the Easter Sunday Raid, a wave of Aichi D3A dive bombers took off from three Japanese carriers to attack Cornwall and Dorsetshire, 320 kilometres (170 nmi; 200 mi) south-west of Ceylon, and sank the two ships.

British losses were 424 men killed; 1,122 survivors spent thirty hours in the water before being rescued by the light cruiser Enterprise and two destroyers.