HMS SYRTIS (Lt M H Jupp) sailed from Lerwick for a patrol area off Kya and Bodo on the Norwegian coast on 16 March 1944. On 20 March she was ordered to move from the Kya area to patrol off Bodo. She was instructed to leave her patrol area after dark on 27 March and was due to arrive at Lerwick on 30 March 1944.

She failed to return from patrol and was reported as lost on 2 April 1944. No signals were received from SYRTIS during her patrol, but it is known from German records that she could not have been lost before 22 March. On 22 March 1944, the 241-ton Norwegian steamer Narvik was sunk by gunfire from a submarine that surfaced just ahead of her. This could only have been HMS SYRTIS.

In response, the Germans launched an anti-submarine patrol in the form of a BV138 flying boat, but nothing was sighted. There were no attacks by ships or aircraft that might account for her loss. The only possibility left is mining and there were several minefields close to her patrol area.