Conversion included fitting an ASDIC anti-submarine dome, a 4-inch naval gun and depth charges.

Lady Shirley went into service in January 1941 and served with the 31st Anti-Submarine Group based at Gibraltar.

[1] On 4 October 1941, while searching for the damaged Silverbelle, Lady Shirley encountered German submarine U-111 engaged in a similar mission south-west of Tenerife, at position 27°15′N 20°27′W / 27.250°N 20.450°W / 27.250; -20.450.

[1] This was the first time that prisoners of war (POWs) were captured from a U-boat operating in the South Atlantic.

[4] On 11 December 1941, a torpedo from U-374 hit Lady Shirley, sinking her in the Straits of Gibraltar at position 35°59′N 5°17′W / 35.983°N 5.283°W / 35.983; -5.283.