'MB6' was a British naval undertaking by Admiral Sir Andrew Cunningham’s Mediterranean Fleet as a complex operation designed primarily to support the MF.3 fast convoy from Alexandria to Malta, but also to cover the ME.4 and AS.4 convoys from Malta and Greece respectively, and to make a carrierborne air attack on Italian installations on the island of Léros (8/15 October 1940).

The MF.3 convoy comprised the 7,506-ton Memnon, 9,816-ton Lanarkshire, 10,492-ton Clan Macaulay and 7,347-ton Clan Ferguson under the close escort of the light anti-aircraft cruisers Calcutta and Coventry, and the destroyers Wryneck and Australian Stuart, Voyager and Waterhen.

'MB6' proper eventually involved the battleships Malaya, Ramillies, Valiant and Warspite, the fleet carriers Eagle and Illustrious, the heavy cruiser York, the light cruisers Gloucester and Liverpool (3^rd Cruiser Squadron), the light cruisers Ajax, Orion and Australian Sydney (7^th Cruiser Squadron), and 16 destroyers including Hasty, Havock, Hereward, Hero, Hyperion, Ilex, Imperial, Janus, Jervis, Juno and Nubian of the 2^nd, 10^th and 14^th Destroyer Flotillas.

The operation also had a number of other objects, including the support of the ME.4 convoy from Malta and the AS.4 convoy from Greece, and a carrierborne air attack on the airfield of Léros in the Italian-held Dodecanese islands group.

At 02.54 on 9 October the fleet was joined at sea by the light cruiser Liverpool and destroyer Diamond.

At 17.15 on 10 October Ramillies, Hasty, Hereward, Hero, Hyperion, Ilex and Nubian detached to refuel at Malta, and at intervals through the rest of the day and during 11 October the other units also detached to refuel in Malta. At 11.05 on 11 October Imperial was mined and badly damaged, and then towed into Malta by Decoy.

At 16.00 the MF.3 convoy reached Malta in company with Orion, Stuart and Vendetta. At this time the main body of the Mediterranean Fleet was 100 miles (160 km) to the south-east of Malta, and here it was sighted and reported by an Italian civil airliner. At 22.45 the ME.4 convoy, which included the river gunboat Aphis, sailed from Malta escorted by the light anti-aircraft cruisers Calcutta and Coventry and the destroyers Wryneck and Waterhen. Late in the evening following the return of all the refuelled ships, the Mediterranean Fleet turned for Alexandria.

To the north-east of Malta, and positioned in anticipation that a convoy would be sailing from Malta to Gibraltar, was an Italian force comprising four destroyers, three torpedo boats and four MAS motor torpedo boats, and this led to the engagement known to the Italians as the Battle of Cape Passero on 12 October.

On learning of the presence of the British warships, Ammiraglio di Squadra Inigo Campioni had ordered a force of destroyers to the area of Cape Bon, in case the British warships intended to pass on from Malta to Gibraltar. In Campioni’s view it was too late for the Italian battleships and cruisers to operate against the convoy.

On patrol at this time was a flotilla of four destroyers and three torpedo boats some 3.5 miles (5.5 km) apart in full moonlight. The Italian vessels were the destroyers Artigliere, Camicia Nera, Aviere and Geniere (Capitano di Vascello Carlo Margotin’s 11a Squadriglia Cacciatorpediniere), and the torpedo boats Ariel, Alcione and Airone (Capitano di Corvetta Banfi’s 1a Squadriglia Cacciatorpediniere).

At 01.37 the most northerly British ship, the light cruiser Ajax under the command of Captain E. D. B. McCarthy, was sighted by Alcione, which was steaming to the east, at a range of 19,600 yards (17900 m) on the Italian ship’s port side. At 01.48, the three torpedo boats were fast closing the British cruiser, which was completely unaware of their approach. At 01.57 Alcione fired two torpedoes from a range of 1,900 yards (1750 m), and Banfi, whose ship was leading the Italian formation, ordered Airone to open fire with her 100-mm (3.94-in) guns, with her sister ships following her into action. Three rounds hit Ajax, two of them striking the bridge and the third the hull 6 ft (1.8 m) below the waterline. Ajax then opened fire on the nearest torpedo boat, Ariel, which was shattered by the British cruiser’s salvoes of 6-in (152-mm) shells and sank 20 minutes later, although she may have been able to fire a torpedo. Capitano di Vascello Mario Ruta, the Italian second in command, and most of the crew were killed.

Airone was the next Italian ship to be hit. She managed to launch two torpedoes before she was disabled, catching fire almost immediately, her bridge and upper deck peppered by smaller-calibre weapons at short range. The Italian ship sank a few hours later, and Banfi was among the survivors. Then Alcione, the only Italian warship undamaged, broke contact at 02.03. Meanwhile, after manoeuvring during the fighting, Ajax resumed her course to the east. At 02.15, her fire-control radar detected two Italian destroyers, whose commander, Margottini, had sighted the firing from the south. A radio malfunction had prevented Margottini from organising an attack in full strength, for three of his destroyers had headed to the north-west, instead of to the north as ordered.

Aviere was battered by a sudden broadside from the British cruiser, forestalling a torpedo attack, and was forced to withdraw to the south with heavy damage. Artigliere managed to fire a torpedo and three full salvoes of 120-mm (4.72-in) shells at 2,800 yards (2560 m) before being hit and crippled. The torpedo missed, but four rounds struck two of Ajax's secondary gun turrets and disabled her radar.

After unsuccessfully firing on Camicia Nera, Ajax broke off the action. She had fired 490 rounds of different calibres and four torpedoes: 13 of her crew had been killed and more than 20 wounded, and the ship needed a month of repairs before she returned to active service.

The disabled Artigliere, with her commander and most officers killed, was taken in tow by Camicia Nera. The two ships were surprised at first light by the heavy cruiser York, which drove off Camicia Nera before sinking Artigliere, whose survivors were rescued by the Italians during the following day.

The support expected from the light warships of the Messina-based 3a Divisione Incrociatori (heavy cruisers Trieste, Trento and Bolzano) and three destroyers of the 14a Squadriglia Cacciatorpediniere did not materialise, but the hospital ship Aquileia recovered 225 survivors.

This action was the Italian navy’s first experience of the Royal Navy’s superior skills and equipment in night actions, and it was immediately clear that the extensive British use of star shells, searchlights and incendiary rounds had to be countered before the Italians could close the technical gap.

At 11.00, to the south-east of Gavdos island, the ME.4 convoy was joined by the AS.4 convoy, which had sailed from Piraeus. In the evening the fleet divided, and Illustrious, Gloucester, Liverpool, Havock, Hereward, Hero and Nubian headed into the Aegean Sea. Early in the morning of 14 October, Fairey Swordfish bombers from Illustrious carried out an attack on the airfield of Léros. At 08.40 Illustrious and her supporting warships rejoined the main body of the fleet, and the combined force then set course for Alexandria.

The tally for the Battle of Cape Passero was 13 men killed and 22 wounded for the British, who also suffered damage to one light cruiser, and 325 men killed for the Italians, who had also lost one destroyer and two torpedo boats, and suffered damage to another destroyer.

In the evening the fleet came under air attack, and at 18.45, some 70 miles (115 km) to the south-east of Crete, Liverpool sustained an air-launched torpedo hit on the starboard side of her bow. At 19.20 the petrol storage compartment exploded, blowing the roof off 'A' turret, the port gun falling into the sea and a fire being started. Decoy and Hereward stood by, and at 22.30 Orion took Liverpool in tow, towing her stern-first at 9.5 kt toward Alexandria escorted by Dainty, Decoy, Diamond and Vampire.

At 01.00 on 15 October the Mediterranean Fleet arrived back at Alexandria.