Operation Vigorous

Operation Vigorous ( 1942, the Battle of mid-June 1942) was a British operation during the Second World War, to escort supply convoy MW11 from the eastern Mediterranean to Malta, which took place from 1942. Vigorous was part of Operation Julius, a simultaneous operation with Operation Harpoon from Gibraltar and supporting operations. Sub-convoy MW11c sailed from Port Said on 11 June, to tempt the Italian battlefleet to sail early, use up fuel and be exposed to submarine and air attack. MW11a and MW11b sailed next day from Haifa, Port Said and Alexandria, one ship being sent back because of defects. Italian and German (Axis) aircraft attacked MW11c on 12 June and a damaged ship was diverted to Tobruk, just east of Gazala. The merchant ships and escorts rendezvoused on 13 June. The British plans were revealed unwittingly to the Axis by the US Military Attaché in Egypt, Colonel Bonner Fellers, who reported to Washington, D.C. in coded wireless messages. The Black Code was later revealed by Ultra to have been broken by the (Italian military intelligence).
The convoy and escorts sailed through "Bomb Alley" between Crete and Cyrenaica under attack from Axis bombers, dive-bombers, torpedo-bombers, E-boats and submarines and were then threatened by the sailing of an Italian battlefleet from Taranto. The British relied on aircraft and submarines to repel the Italian fleet in the absence of battleships and aircraft carriers but only one heavy cruiser was sunk. When the Italian battleships were within the British convoy and escorts were ordered to turn back and wait for the Italians to suffer losses from torpedo-bombers, bombers and submarines but little more damage was inflicted and after several more turns towards and away from Malta, the convoy and escorts returned to Alexandria on 16 June. The Battle of Gazala (26 May – 21 June) was being fought in Libya during Operation Julius and beginning on 14 June, the British defeat forced the Eighth Army to withdraw eastwards, losing landing grounds from which aircraft could provide air cover for MW11.
Operation Julius was a British defeat and only two merchant ships from Operation Harpoon, the simultaneous convoy from Gibraltar, reaching Malta to deliver supplies. In the absence of air cover and the suppression of Axis air power lining the routes to Malta, the central Mediterranean had been closed to British ships. Malta could not be revived as an offensive base and to provide some aviation fuel for the defending fighters, the British resorted to the expedient of running supplies through the blockade by submarine. No more convoys were attempted from the eastern Mediterranean until the Eighth Army conquered Libya in October. More Spitfires were delivered to Malta during July and increasing losses forced the and to reduce the tempo of operations. A limited return to offensive operations was made against Axis convoys to Libya and Operation Pedestal in August delivered four merchant ships and an oil tanker from Gibraltar, which further revived Malta as an offensive base, despite the loss of most of the convoy and many naval ships.
Background.
Malta.
Siege, 1942.
Axis bombing smashed the docks, ships, aircraft and airfields by the end of April 1942 and then the bombing was switched to targets preliminary to invasion: camps, barracks, warehouses and road junctions. After 18 April, German bombing suddenly stopped and Italian bombers took over, regularly bombing with small formations of aircraft. During the month, Axis aircraft flew more than against all but fighter sorties. The British had lost down in combat against losses during the dropping of of bombs, three times the March figure, on the docks, on airfields. The bombing demolished or damaged were killed and wounded; good shelters existed but some casualties were caused by delayed-action bombs. Rations of meat, fats and sugar were cut further and on 5 May, the bread ration was cut to per day, enough to last until late July; pasta rations had already been stopped and there had been a poor winter potato harvest.
Three destroyers, three submarines, three minesweepers, five tugs, a water carrier and a floating crane were sunk in port and more ships damaged. The island continued to function as a staging post but the Axis bombing campaign neutralised Malta as an offensive base. Two boats of the 10th Submarine Flotilla had been sunk, two were damaged in harbour and on 26 April the flotilla was ordered out because of mining by small fast craft, which were undetectable by radar and inaudible during the bombing; the surviving minesweepers were too reduced in numbers to clear the approaches. Three reconnaissance aircraft remained and only sorties were flown, eleven more by FAA aircraft during the month and by the start of June, only two Fairey Albacores and two Fairey Swordfish were left.
Offensive operations.
From December 1941, bombing neutralised Malta, decrypts of Italian cipher messages showed more sailings and fewer losses and on 23 February 1942, an Italian "battleship convoy" reached Tripoli. By the end of February, had crossed without escort and a blackout caused by a change to the machine in early March made little difference to the British for lack of means. After the British broke supply journeys had been made by May, only nine being spotted by air reconnaissance. On 14 April, five Malta aircraft were shot down and the submarine was lost. On 10 March, the cruiser was sunk by a U-boat and on 10 May, three of four destroyers were sunk by the . In February and March, Axis losses were of supplies, those sent in April fewer than one percent and May losses were 
The Axis was able to reinforce North Africa sufficient for Rommel to try to attack before the British. In late April, the British Chiefs of Staff ruled that there would be no convoy to Malta in May, because the Italian fleet could be expected to sail and convoy would need battleship and aircraft carrier cover, which was not available. An operation to fly Spitfires to Malta succeeded and anti-aircraft ammunition was to be supplied by fast minelayer, with which Malta must hold on until mid-June, when the situation in the Western Desert. Should Martuba or Benghazi in Cyrenaica have been captured by the Eighth Army, a westbound convoy from Alexandria might survive without cover from battleships and aircraft carriers. It would also be known if aircraft had been diverted to the Russian Front and if the crisis in the Indian Ocean had abated, sufficient for ships to escort a fast convoy from Alexandria.
Operation Hercules () was an Axis plan to invade Malta and during 1942, reinforcement of the in Sicily and the bombing campaign against the island led to speculation that it was the prelude to invasion. Gleanings from prisoners of war and diplomatic sources led to a certain apprehension about the meaning of troop movements in southern Italy. The absence of evidence from signals intelligence and air reconnaissance led to a conclusion that an invasion was not imminent but the need to protect the source of information meant that this was not disclosed by the British. That preparations were being made was revealed on 7 February through the decryption of Enigma messages but by 23 March the scare died down and more bombing was expected. By 31 March the progress of the Axis bombing campaign led to a prediction that the attempt would be made in April but this was soon discounted because although the bombing offensive increased from in February, to in March, in April, Enigma decodes showed that there were still 