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).

[3] Denbigh Castle, the only ship of her name to serve in the Royal Navy,[4] was ordered on 19 December 1942 and laid down by John Lewis & Sons at their shipyard in Aberdeen, Scotland, on 30 September 1943.

Having completed training, Denbigh Castle arrived at Scapa Flow on 29 January to join the 7th Escort Group.

The destroyer Serapis transferred her medical officer over and the corvette Bluebell came alongside around 00:45 to receive casualties, and Butcher ordered as many ratings aboard her as he thought he could spare.

The ship began to slowly list with the ebbing tide and the officers abandoned her at 09:05; five minutes later she capsized and slid into deeper water.

The intense cold made later efforts to retrieve or destroy secret documents and equipment still aboard extremely difficult, but the diving team from the light cruiser Bellona did manage to demolish the radar office.