In October 1941, Vian was given command of the 15th Cruiser Squadron (flag in , stationed at Alexandria. The main naval tasks at this stage of the Mediterranean campaign were to ensure the survival of Malta as a British possession and military base by the protection of supply convoys while preventing Italian convoys supplying their forces in north Africa. Secondary tasks included the supply and artillery support of Allied military actions in north Africa and elsewhere, such as a successful bombardment of Derna in December. Vian's first convoy was in December 1941 and led to the First Battle of Sirte. This was, in effect, a series of skirmishes between British and Italian warships escorting desperately needed supply convoys. Overall, the fight was inconclusive, but both sides managed to deliver the supplies. There were several sorties to support the army and to intercept Italian convoys. On one such operation, in early March 1942, Vian's flagship, HMS "Naiad", was torpedoed and sunk by . Vian transferred his flag to and later to .