The ship was built by William Hamilton and Company, Port Glasgow, with turbine engines supplied by J. Samuel White of Cowes. She was laid down on 17 January 1938, and launched on 7 February 1939.[1]
Sphinx was commissioned in July 1939, and assigned to the 5th Minesweeping Flotilla, based at Dover as part of the Nore Command. The flotilla carried out minesweeping in the English Channel and the North Sea until December, when it was transferred to Rosyth.[1]
On the morning of 2 February 1940 the Flotilla was minesweeping in the Moray Firth, 15 miles north of Kinnaird Head, in position, when it came under attack by German aircraft. Sphinx was hit by a bomb, which penetrated the foredeck and exploded, killing five men, including the commanding officer Cdr. John Robert Newton Taylor. The crippled ship was taken under tow by, but eventually capsized[1] 17 hours after being bombed. rescued 46 of her crew, but 49 men were lost.[2] The wreck later drifted ashore two miles north of Lybster,[1] and was eventually sold for scrap.
On 7 June 1940 the OBE was awarded to Sphinxs Senior surviving Officer and two members of the crew, and there were five Mentions in Despatches, three to crewmen of Sphinx and two from Boreas.
Sphinx is briefly referenced in an episode of the British sitcom Only Fools and Horses. In the third of the 1996 Christmas special episodes, Time on Our Hands, Uncle Albert describes the ship as a frigate on which he served in the Adriatic during World War II. He explains to the main protagonist, Delboy, how a fictional Captain Kenworthy faked an outbreak of cholera aboard the ship to distract the crew from their other worries.[3]