HMS Lagan

HMS Lagan (K259) was a River-class frigate of the Royal Navy (RN). Lagan was built to the RN's specifications as a Group II River-class frigate. She served in the North Atlantic during World War II.

As a River-class frigate, Lagan was one of 151 frigates launched between 1941 and 1944 for use as anti-submarine convoy escorts, named after rivers in the United Kingdom. The ships were designed by naval engineer William Reed, of Smith's Dock Company of South Bank-on-Tees, to have the endurance and anti-submarine capabilities of the Black Swan-class sloop sloops, while being quick and cheap to build in civil dockyards using the machinery (e.g. reciprocating steam engines instead of turbines) and construction techniques pioneered in the building of the Flower-class corvettes. Its purpose was to improve on the convoy escort classes in service with the Royal Navy at the time, including the Flower class.

After commissioning in December 1942, Lagan served in convoy escort missions and participated in anti-submarine warfare exercises off Lough Foyle. On 12 May 1942, Lagan, with HMS Biter (D97) and HMS Broadway (H90), sunk the GS U-89 (1941). The next day, Lagan and HMCS Drumheller sunk GS U-753.

Whilst Lagan was part of Convoy ON 202, she was attacked by GS U-270. At 04:57 on 20 September 1943, a GNAT torpedo struck the stern of Lagan, causing critical damage to the ship and 29 dead. She was towed by the tugboat HMS Destiny (W 115) to Mersey, arriving on 24 September, where Lagan was declared a constructive total loss. The wreck was sold for scrap in Troon on 21 May 1946.