She served in World War II as a minesweeper and was sunk by the German motor torpedo boat S-58 off Cap de Garde, near Bône, Algeria.

They were generally armed with a 12-pounder 76 mm (3.0 in) quick firing low angle gun and three 20mm Oerlikons in single mountings.

[1] Around April of the same year, Horatio received a new commanding officer, Temporary Lieutenant Charles Alfred Lemkey, who was to remain the trawler's captain for remainder of its career.

On 7 July 1942, Leading Seaman William Harold Leon Simpson RNPS was awarded the Distinguished Service Medal for "courage and steadfastness in beating off an attack on H.M.T.

"[2] On 7 January 1943 Horatio was sunk by the German motor torpedo boat S-58 off Cap de Garde, near Bône, Algeria.