'MD4' was the British naval undertaking by Admiral Sir Andrew Cunningham’s Mediterranean Fleet to support the 'Tiger' (ii) convoy, hitherto the responsibility of Vice Admiral Sir James Somerville’s Gibraltar-based Force 'H', on its passage to the east from Cap Bon through the eastern part of the Mediterranean Sea to Alexandria (6 May 1941).

On 6 May the warships of the Mediterranean Fleet which departed Alexandria were the battleships Barham, Valiant and Warspite, the fleet carrier Formidable, the light cruisers Ajax, Orion and Australian Perth, the cruiser minelayer Abdiel and the destroyers Griffin, Havock, Hotspur, Imperial, Jaguar, Jervis, Juno, Kandahar, Kimberley, Kingston, Napier and Nizam.

The 9,776-ton commissioned fast supply ship Breconshire also departed Alexandria to refuel destroyers at Malta. The light anti-aircraft cruisers Calcutta, Dido and Phoebe, and the destroyers Hereward, Hero, Ilex and Isis also departed Alexandria to escort the MW.7A fast Malta convoy with four supply ships (6,000-ton Settler, 6,655-ton Norwegian Thermopylae, 10,218-ton Danish Amerika and 6,798-ton Norwegian Talabot) together with the tug St Issey after the Mediterranean Fleet was already at sea.

After responsibility for its safety passed from Force 'H' to the Mediterranean Fleet, the 'Tiger' (ii) convoy and supporting ships continued eastward with no problems until midnight on 8 May, when a mine exploded in the 12,436-ton British New Zealand Star's paravanes. Within three minutes the 9,228-ton British Empire Song had struck two mines, or exploded them close aboard in her paravanes, and was forced to leave the line and report a fire in the hold containing ammunition. Foresight and Fortune left the screen and stood by Empire Song, the former then going alongside to take off the freighter’s crew. After consideration it was decided that the ship might be saved and a volunteer party from Foresight, comprising Royal Navy and Merchant Navy officers and ratings, was sent over by whaler just as Empire Song blew up, hurling tanks, ammunition and portions of her structure over the area. The whaler was sunk, fortunately with the loss of only one life, and the two destroyers rejoined the convoy with Foresight carrying 130 survivors and therefore being ordered to Malta to land these men.

The modern light anti-aircraft cruisers Dido and Phoebe joined at 06.00 on 9 May, and the older anti-aircraft cruisers Calcutta, Carlisle and Coventry followed at 08.00. The main force of the Mediterranean Fleet was met at 15.15.

On this eastward passage, destroyers were again detached to carry out another bombardment of Benghazi: 866 4.7-in (119.4-mm) shells were landed in the harbour area in just nine minutes.

'Tiger' (ii) ended with the convoy’s arrival at Alexandria at 12.000 on 12 May having suffered the loss of only Empire Song. The army and the RAF thereby benefited from the arrival of 238 tanks, 64 Hawker Hurricane fighters and a considerable tonnage of ammunition and other supplies for use in the forthcoming Battle of Gazala.