Claude Auchinleck, the commander-in-chief Middle East Command, had decided not to defend Tobruk for a second time, due to the cost of bringing supplies in by sea; its minefields and barbed wire had been stripped for use in the Gazala Line to the west.

On 20 June the Panzerarmee Afrika attacked Tobruk with massed air support, penetrated a weak spot on the eastern defensive perimeter and captured the port.

Following the arrival of the German Afrika Korps commanded by Erwin Rommel in Operation Sonnenblume in March, Axis forces retook much of the lost territory in Cyrenaica; Tobruk was cut off and besieged between April and December 1941.

The Allied occupation of Tobruk was a threat to the Axis communications, it denied them the use of the port, and it tied down four Italian divisions and three German battalions, a force twice the size of the garrison.

[10] On 1 May 1942, a meeting of Axis leaders was held at the Berghof in Berchtesgaden, with Adolf Hitler and Albert Kesselring, the Wehrmacht Oberbefehlshaber Süd (Commander-in-Chief South), Benito Mussolini and Ugo Cavallero, the Chief of the Defence Staff, for Italy.

[14] In a meeting held in Cairo on 4 February 1942, the service commanders-in-chief of Middle East Command considered what their course of action should be in the event of a further successful Axis offensive, the front line at that time being only 30 mi (48 km) west of Tobruk.

Auchinleck drafted orders for Lieutenant-General Neil Ritchie, the commander of the Eighth Army, that he was to make every effort to prevent Tobruk from being taken but he was not to allow his forces to be surrounded there.

If the fall of Tobruk was imminent, "the place should be evacuated and the maximum amount of destruction carried out in it", while a firm defence line should be established further east on the Egyptian border.

Auchinleck began to reassess the Tobruk position; neither he nor Ritchie wanted to lose the considerable stocks of fuel, munitions and other stores which had been built up at the port for Operation Acrobat.

Ritchie informed Auchinleck that he would attempt to hold the Acroma–El Adem line with troops from XXX Corps but warned that if this failed, Tobruk might either become "temporarily isolated" or be evacuated and asked which option was to be taken.

Many non-essential troops had been evacuated, there remained a number of administrative units of the HQ 88th Sub-Area ( Brigadier Leslie Thompson) including ten transport companies and a Naval Establishment (Captain P. N. Walter RN).

[34] Wishing to exploit the disorganisation of the Eighth Army, Rommel issued his orders for the assault on 18 June and reconnaissance of deployment areas commenced early the next day.

In the west, XXI Corps was to make a feint attack to pin down the South African brigades, while in the east, the 90th Light Division was to prevent relief attempts on Tobruk by the Eighth Army.

Gruppe Menny began its attack at 7:00 a.m., which coincided with the opening of the artillery barrage, which had been delayed by late arrivals at their positions; a breach in the line between two strong points had been made at 7:45 a.m.

The Ariete Division, the spearhead of XX Corps, had failed to penetrate the line held by 2nd Battalion, Cameron Highlanders and were redirected into the breach made by the Afrika Korps and then sent westwards towards Fort Pilastrino.

[42] By 1:30 p.m., the Afrika Korps had reached their objective, the Kings Cross road junction on the crest of the Pilastrino Ridge and overlooked the town of Tobruk, about 9 km (6 mi) to the north.

The last obstacle for the panzers was a motley of artillery units which made a determined defence, including the use of several 3.7-inch anti-aircraft guns against the German tanks; Rommel later praised their "extraordinary tenacity".

The final evacuation of small naval vessels had been carried out under fire; fifteen craft escaped but twenty-five, including a minesweeper, were sunk in the harbour or lost to air attacks on the passage to Alexandria.

The remnants of the British and Indian units in the eastern sector of the fortress prepared themselves for all-round defence; the South African brigades had not been engaged except for some diversionary activity.

Although Ritchie had ordered the 7th Armoured Division to move north towards Sidi Rezegh, to the south-east of the Tobruk perimeter, there is no evidence that they advanced very far or threatened the Axis cordon.

Some units did not receive the order; the 2nd Battalion, 7th Gurkha Rifles, on the eastern perimeter, fought on until that evening, while the Cameron Highlanders continued fighting until the morning of 22 June.

Rommel had overwhelming air support at Tobruk, because almost all of the Allied fighter aircraft had been withdrawn and were out of range; Luftwaffe bombing played an important role in breaching the defences.

The conference also received a telegram from British Minister-Resident in the Middle East Richard Casey warning that the defeat opened the possibility of an Axis invasion of Egypt.

Churchill and others attributed the defeat to the loss of Tobruk four days before; Driberg denied this was a major factor, suggesting instead that it was part of a wider swing to the left and away from the established political parties.

When a right-wing Conservative, Sir John Wardlaw-Milne, tabled a motion of no-confidence in the coalition government, there was speculation that it might go the way of the Norway Debate, which had led to the resignation of the previous prime minister, Neville Chamberlain, in May 1940.

At the Italian armistice in September 1943, many prisoners escaped, including Klopper, who was rescued by Popski's Private Army (Major Vladimir Peniakoff) which was operating nearby.

[68] In the afternoon of 21 June, the day of the surrender, Kesselring visited Rommel's headquarters and reminded him of the agreement that the invasion of Malta would follow the capture of Tobruk and that his aircraft were already returning to Italy.

He had the latest pessimistic report from the U.S. military attaché Bonner Fellers in Cairo to Washington on the British dispositions, which concluded with the phrase; "If Rommel intends to take the Delta, now is the time"; the supplies captured at Tobruk made that possible.

[69] On 22 June, Rommel by-passed the chain of command by writing directly to Mussolini via the German attaché in Rome, Enno von Rintelen, requesting that the offensive be allowed to continue and that the Malta invasion be postponed to preserve his air support.

Hitler replied the next day with an effusive letter which agreed with Rommel's suggestion and urged Mussolini not to let the opportunity slip away, stating that "the goddess of success passes generals only once".