'Quadrangle' was a British naval undertaking by Admiral Sir Henry Harwood’s Mediterranean Fleet to expedite a series of four convoys into Malta from Egypt (6 December 1942/1 January 1943).

Given the success of the previous 'Stoneage' and 'Portcullis' convoy operations, Harwood decided that these final relief convoys for Malta should each consist of two merchantmen with minimal escort, sailing as far as Benghazi with normal Western Desert convoys before breaking away to the north-west toward Malta under final escort of Rear Admiral A. J. Power’s Malta-based Force 'K', whose average strength was one light cruiser and five destroyers, in case the Italians sortied from Taranto.

The four convoy operations were designated 'Quadrangle A', 'Quadrangle B' and 'Quadrangle C' in December 1942, and then 'Quadrangle D' in January 1943. On each occasion the opportunity was taken to pass empty ships to the east from Malta, this number including the four survivors of the 'Pedestal' convoy.

The MW.15 ('Quadrangle A') convoy comprised the 6,802-ton US American Packer and 6,985-ton British Ozarda, which departed Port Said on 6 December under escort of the minesweepers Boston, Cromarty and Whitehaven. The destroyer Paladin and escort destroyers Dulverton and Hurworth joined from Alexandria on 7 December, and the escort was reinforced by the escort destroyer Belvoir from Tobruk on 10 December. On the same day the light cruiser Orion and escort destroyers Aldenham, Croome, Exmoor and Hursley joined from Malta, and delivered the convoy to the island at 22.30 on the same day.

The MW.16 ('Quadrangle B') convoy comprised the 4,635-ton British Clan MacIndoe, 2,290-ton British Robert Maersk and 6,233-ton Dutch tanker Erinna escorted by Belvoir and Paladin from Alexandria, and Hurworth was also with the convoy to take in the Benghazi ship before rejoining the MW.16 convoy on 12 December, when Paladin detached to Malta after dark. The convoy was met from Malta by Aldenham, Croome, Exmoor and Hursley on 13 December, and reached Malta in the early morning of the following day.

The MW.17 ('Quadrangle C') convoy comprised the 7,129-ton British Fort Tadoussac and 7,174-ton British Ocean Voyager, which departed Port Said on 12 December under escort of Dulverton, Tetcott and Free Greek Pindos to Alexandria, where the convoy was held until 17 December, when it sailed with the Benghazi ships escorted by the destroyer Pakenham and escort destroyers Beaufort, Dulverton, Pindos and Tetcott. Met by Orion and rejoined from Benghazi by Beaufort, the convoy reached Malta on 21 December. During this passage Harwood noted in his war diary that as some 14 ships, held loaded at Gibraltar ready to proceed to Malta, were no longer required and were therefore to be dispersed as the eastern supply line was now regarded as safe and adequate for the further supply of the island.

The MW.18 ('Quadrangle D') convoy was the last of the series, and comprised the 7,176-ton US Daniel H. Lownsdale and 6,900-ton Panamanian Yorba Linda, escorted by Aldenham, Exmoor, Hursley and Hurworth. The convoy departed Alexandria on 28 December and was ordered into Benghazi two days later as there were indications that an Italian battleship was at sea. The convoy sailed again at 19.00 on the same day and reached Malta on 31 December, completing the December 1942 series of convoys to Malta.

During this period Malta’s harbour facilities were poor, the waterfront having suffered some 30 months of air attacks, and the waters in and around the harbour were restricted by wrecks. Thus the clearance of empty ships assumed considerable priority. The ME.11 convoy therefore sailed from Malta on 7 December in the 'MH2' operation. This convoy comprised the mobile survivors of 'Pedestal' and the MW.13 convoy’s ships, in all the 9,312-ton Dutch Bantam, 12,791-ton British Brisbane Star, 8,983-ton British Denbighshire, 12,806-ton British Melbourne Star, 7,939-ton US Mormacmoon, 8,535-ton British Port Chalmers, 7,101-ton US Robin Locksley, 7,795-ton British Rochester Castle and 6,900-ton Panamanian Yorba Linda. The convoy was escorted from the island by the light cruiser Orion, destroyers Pakenham, Petard and Free Greek Vasilissa Olga, and escort destroyers Aldenham, Belvoir, Croome, Dulverton, Exmoor, Hursley, Tetcott and Free Greek Pindos.

The escort was partially exchanged at the Tripoli rendezvous to bring in the MW.16 convoy, Orion, Aldenham, Croome, Exmoor and Hursley leaving. Later Belvoir was sent to Tobruk to fuel while Dulverton and Pindos took Yorba Linda to Alexandria, and the convoy reached Port Said at 07.00 on 11 December.

The ME.12 convoy comprised the 6,679-ton US Agwimonte, 6,796-ton US Alcoa Prospector, 9,795-ton British Glenartney and 13,890-ton British Suffolk, escorted by Orion, Petard, Aldenham, Belvoir, Croome, Exmoor, Hursley, Hurworth, and Vasilissa Olga. Orion detached at 09.00 on 19 December to join the MW.17 convoy, Petard and Vasilissa Olga detached off Alexandria, and the convoy reached Port Said at 20.00 on 20 December.

The last eastward convoy of 1942 was the ME.14 convoy, which sailed on 28 December with the 6,802-ton US American Packer, 4,635-ton British Clan MacIndoe, 6,233-ton Dutch Erinna and 6,985-ton British Ozarda escorted by the light anti-aircraft cruiser Euryalus and escort destroyers Beaufort, Dulverton, Tetcott and Pindos. The convoy was attacked unsuccessfully by a submarine on 30 December, Beaufort being detached to hunt the boat. Euryalus left the convoy to return to Malta at 18.00 on 30 December, Beaufort rejoined on the following day, and the convoy reached Port Said on 1 January 1943.