The Flower-class corvettes had their origins in a sketch design by the Smiths Dock Company which was based on their whaling ship Southern Pride, but lengthened by 9.1 metres (30 ft).

The engine drove a single propeller and Mallow could reach a top speed of 16 knots (30 km/h; 18 mph).

She carried 230 long tons (230 t) of fuel oil, which gave her a range of 3,450 nautical miles (6,390 km; 3,970 mi) at 12 knots (22 km/h; 14 mph).

[3][6] In 1944, Mallow's AA armament included a total of six single 0.79 in (20 mm) Oerlikon cannons, and one 2-pounder "pom-pom".

[1] Mallow was built by the firm of Harland and Wolff at Belfast, Northern Ireland under as yard number 1065,[8] and was ordered on 19 September 1939, laid down on 14 November, launched on 22 May 1940, and commissioned on 2 July.

In mid-October, the group was assigned to escort Convoy HG 75 from Gibraltar to Liverpool;[13] Mallow and the Shoreham-class sloop HMS Rochester participated in sweeps west of Gibraltar against the concentration of German U-boats awaiting the departure of the convoy, and together sank U-204 on the 19th.

[14] Noall was later made a Companion of the Distinguished Service Order for "skill and enterprise in dealing with submarines" whilst commanding Mallow.

During her final escort of 1944, she was detached from convoy KMS 66 as her crew was not considered "politically reliable" because they were not aligned with Josip Broz Tito's Partisan forces.

[19] The requirement to return Partizanka was a painful blow to the Yugoslavs, as she was one of few modern warships in service with them at the time.