[4][6] The ship carried 368 long tons (374 t) of oil giving a range of 3,500 nautical miles (6,500 km; 4,000 mi) at 15 knots (28 km/h; 17 mph).

[8] On commissioning, Westcott joined the 13th Destroyer Flotilla of the Grand Fleet, based at Rosyth in support of the Battlecruiser Force,[9][10] remaining there for the remainder of the war.

[3][14] In February 1920, Westcott was deployed to the Mediterranean, shelling Turkish forces during the Greco-Turkish War, before returning to Britain in August.

[3] On the outbreak of the Second World War, Westcott was still allocated to the Fourth Submarine Flotilla, and was having her armament restored to suit her for full operational service.

Westcott was sent to Brest, but collided with the coaster Nyroca on 17 June, with both ships returning to the United Kingdom empty.

[24] On 4 July, Westcott joined the 4th Destroyer Flotilla, based at Devonport for escort duties in the North Atlantic.

[3] On 2 September 1940, Westcott, with the destroyer HMCS Skeena, the sloops Lowestoft and Scarborough and the corvette Periwinkle, joined inbound Atlantic convoy SC.2 as escort.

[17] On 16 January 1942, the troopship MV Llangibby Castle was torpedoed and damaged by the German U-boat U-402, but managed to reach Horta in the Azores.

[33][34] On 19 April, Westcott formed part of the escort for the American aircraft carrier Wasp during Operation Calendar, an attempt to deliver vitally needed Spitfire fighters to Malta.

[3][35] The Spitfires were quickly lost, however, and as a result another attempt was made to reinforce Malta's air defences, Operation Bowery.

Both convoys came under heavy air attack, and on 14 June, the cruiser Liverpool was damaged by a torpedo dropped by an Italian aircraft.

The three ships came under continued Italian torpedo-bomber attacks after they had left the convoy, and on 16 April, Westcott was hit by anti-aircraft fire from Liverpool, killing three of her crew.

[3][42][43] Five merchant ships out of fourteen, including the vital tanker SS Ohio, finally made Malta by 15 August.

Westcott formed part of the Centre Task Force, covering the landings at Oran in Algeria on 8 November.

When the Vichy French submarines Actéon and Argonaute attempted to attack the Allied fleet, they were sunk by Westcott and Achates.

[3] This involved removing one boiler and its associated funnel, allowing additional oil bunkers to be fitted, extending the ship's range by as much as 600 nautical miles (1,100 km; 690 mi).

[49][50] Withdrawn from service in June 1945, Westcott was sold to the British Iron & Steel Corporation (BISCO) to be scrapped the following year.