'MF3' was a British naval undertaking by Admiral Sir Andrew Cunningham’s Mediterranean Fleet in support of the passages of the MW.8A and MW.8B convoys from Alexandria to Malta (16/20 January 1942).

Both convoys departed Alexandria on 16 January, although at different times. The MW.8A convoy comprised the 7,540-ton British Ajax and 6,655-ton Norwegian Thermopylae escorted by the light anti-aircraft cruiser Carlisle and destroyers Arrow, Griffin, Hasty and Hero, and the MW.8B convoy comprised the 8,063-ton British City of Calcutta and 7,347-ton British Clan Ferguson escorted by the destroyers Gurkha, Legion, Maori and Free Dutch Isaac Sweers.

After last-minute casualties as it left harbour, Rear Admiral P. L. Vian’s Force 'B', which was to provide cover for the merchant ships and their close escorts, comprised the light anti-aircraft cruisers Dido, Euryalus and Naiad, and the destroyers Foxhound, Havock, Hotspur, Kelvin and Kipling. Additionally, the Malta-based Force 'K' was ordered to despatch the light cruiser Penelope and the destroyers Jaguar, Lance, Lively, Sikh and Zulu from Malta on 17 January to rendezvous on the following day.

During the passage of the two convoys, which were due to join on 18 January, Gurkha was torpedoed by Kapitänleutnant Hermann Hesse’s U-133 and set on fire. Determined action on board, and by the crew of Isaac Sweers, made it possible to rescue a large part of the crew, but the crippled destroyer had to be scuttled as she was being towed toward Sidi Barrani.

Late on 17 January Thermopylae straggled as a result of her inability to maintain the convoy speed and also of steering difficulties, so she was detached with the light anti-aircraft cruiser Carlisle and destroyers Foxhound and Hotspur, and ordered to make for Benghazi. The group was attacked at about 09.30 on 19 January and Thermopylae, hit and set on fire, had to be sunk by one of the destroyers. Some 261 survivors were rescued by the two destroyers, out of a total crew and passenger list of 385.

The remainder of the convoys made their rendezvous with Force 'K' at 13.15 on 18 January, Maori transferred to Force 'K' for Malta and Jaguar to the Alexandria force, and the escorts parted company at 19.30. Although attacked from the air, all the ships had reached Malta by mid-afternoon on 19 January.