HMS Alnwick Castle was one of 44 Castle-class corvettes built for the Royal Navy during the Second World War.

Completed in late 1944, the ship served as a convoy escort until the end of the war, helping to sink one German submarine.

The Castle-class corvette was a stretched version of the preceding Flower class, enlarged to improve seakeeping and to accommodate modern weapons.

The Castles carried enough fuel oil to give them a range of 6,500 nautical miles (12,000 km; 7,500 mi) at 15 knots (28 km/h; 17 mph).

A Type 277 search radar and a HF/DF radio direction finder rounded out the Castles' sensor suite.