Proceeding via Belfast, Northern Ireland, Leamington arrived at Plymouth, England, on 15 November. There, the destroyer was allocated to the 2d Escort Group, Western Approaches Command, based at Londonderry. She conducted convoy escort missions across the Atlantic into 1941. While in the screen of Convoy SC-48 as it was being attacked by German U-boats for more than a week Leamington teamed with the destroyer HMS Veteran in sinking U-207 off the east coast of Greenland on 11 September.

On 27 March 1942, Leamington added another "kill" to her record when she and three other destroyers sent U-587 to the bottom as the U-boat threatened Middle East-bound troop convoy WS-27. That summer, as the flush decker steamed toward North Russia in the screen of the ill-fated convoy, PQ-17, the powerful German battleship Tirpitz was reported on the prowl. Since the massed convoy would present too easy pickings for such a powerful adversary, the ships were scattered. However, such tactics exposed the Allied ships to the attacks of German U-boats and aircraft. As a result, 23 of the 34 ships in PQ-17 were sunk. No other Russian convoy during the entire war suffered so severely.

Leamington was refitted at Hartlepool, England, between August and November 1942 and then resumed convoy escort missions in the Atlantic. On 12 November, the Panamian registry merchantman SS Buchanan was torpedoed by U-224. Thirteen days later, Leamington, assisted by aircraft, located the last of the freighter's four lifeboats and took aboard its 17 uninjured sailors.

In October 1942, the Royal Navy transferred Leamington to the Royal Canadian Navy, who employed her in the defense of shipping in the western Atlantic over the next 14 months. She experienced extremely bad weather, with extensive icing conditions, while operating in the North Atlantic in late 1942 and early 1943. At one point, the ship reached Halifax after a severe gale on 22 January 1943, coated from bridge to foc'sle deck with ice varying from 2 to 10 feet thick.

On 14 May 1943, Leamington collided with USS Albatross (AM-71) and was docked at Halifax for repairs but managed to be seaworthy again by the end of the month. She then sailed south to Norfolk, which she reached on 27 June, and underwent permanent repairs there until September.

Departing Halifax on 22 December, Leamington returned to the British Isles and reverted to Royal Navy control. After a period of service based at Rosyth, Scotland, the flush-deck destroyer was placed in reserve at the Tyne. However, on 16 June 1944, the British loaned the ship to the Russians, who renamed her Zguchij. She served under the Russian flag through 1949 and was returned to Great Britain in 1950. She was subsequently broken up for scrap at Newport, England, on 26 July 1951.

 Former name:USS Twiggs (DD 127)