'MC9' was a British naval undertaking by Admiral Sir Andrew Cunningham’s Mediterranean Fleet to cover the MW.6A convoy from the eastern Mediterranean to Malta (19/23 March 1941).

The close escort of the four-ship convoy (8,917-ton City of Manchester, 7,347-ton Clan Ferguson and 10,496-ton Perthshire from Haifa and 8,039-ton City of Lincoln from Alexandria) comprised the light cruiser Bonaventure, the light anti-aircraft cruisers Calcutta, Carlisle and Coventry as well as four destroyers. Under Cunningham’s command, the 'MC9' distant cover for this convoy was provided by Force 'A' comprising the battleships Barham, Valiant and Warspite, the fleet carrier Formidable, and the destroyers Havock, Hero, Ilex, Jaguar, Janus, Jervis, Juno, Mohawk and Nubian. On 21 March Force 'B', comprising the heavy cruiser York, the light cruisers Ajax, Gloucester, Orion and Australian Perth, and the destroyers Hasty, Hereward and Australian Stuart and Vendetta covered the convoy after refuelling at Souda Bay in northern Crete.

The whole operation passed without detection by German and Italian reconnaissance aircraft, and by the Italian submarines Malachite and Smeraldo, which were patrolling in the area to the south-east of Crete. However, after the convoy had reached Malta, two of its ships, City of Lincoln and Perthshire were damaged on 23 March in the course of an air raid.