- The perimeter defenses are breached, and the fall of Tobruk is less than 12 hours away. -
On 20 June, there was a feeling within Tobruk that Rommel's main forces had swept on eastwards after the tail of Eighth Army. In fact, during the darkness of the previous night Rommel had brought the Afrika Korps round to face the eastern perimeter of the fortress ready for an assault. At 0520hrs a massed artillery bombardment fell on the south-eastern corner of the compound and was soon joined by a sustained attack by Axis aircraft and dive-bombers. Just before 0700hrs German infantry crept forwards and began their assault on the outer defences, giving cover to the engineers who moved up to make crossings of the anti-tank ditch. Within an hour breaches had been made and tanks had crossed over the obstacles, through the minefields and wire, and were dealing with the main British defences.
Both the 15. and 21.Panzer divisions urged their total of 90-plus tanks through the gaps before the British armour could react. Over to their left the 132a Divisione Corazzata 'Ariete' was also attempting its own break-in. It was almost 1000hrs before British tanks reached the area of the Axis assault and clashed with the German armour. For a while this intervention helped the infantry resist the enemy around the inner defensive position. So successful were they that a report was passed on to Maj. Gen. H. B. Klopper  that the situation was in hand. Shortly before midday the state of affairs changed dramatically when the two Panzer divisions launched a strong attack and broke through the last defensive barrier. Within an hour German tanks had pushed aside most of the tanks of 32nd Army Tank Brigade and were closing on an area of higher ground termed 'Kings Cross' - the junction of the roads to El Adem and Bardia. By 1400hrs the 21.Panzer Division was just eight kilometres from the harbour and shelling the town.
By the end of the afternoon Rommel had tanks in Tobruk itself with infantry starting to mop up British resistance and prevent any escapees embarking from the port. A great swathe had been cut into the Tobruk fortress area and parties of Germans and Italians were clearing out British positions throughout the eastern side of the defensive zone. The commander of No. 88 Sub-Area in charge of all the supply dumps, Brigadier Thompson, watched the enemy drawing closer and obtained permission from the commanding general to begin the demolition of all supplies under his command. Fires were lit, equipment blown up and great oil tanks set ablaze, sending a plume of black smoke skywards over the doomed fortress.
The 15.Panzer Division had meanwhile moved westwards along the Pilastrino Ridge and was closing on Maj. Gen. Klopper's headquarters located at the end of the ridge in Fort Pilastrino. At around 1600hrs Klopper's staff sighted these tanks and the general concluded that his headquarters would be overrun in a matter of minutes. He ordered his staff to destroy all documents and equipment and to disperse. The signal office and telephone exchange and virtually all of the radio sets were demolished. At the last moment, the tanks moved away, directed to the south-west and the rear of the untouched British defences. Klopper now decided to set up a command post at the 6th South African Brigade's headquarters in the north-western end of the fortress, but was now hampered in exercising command by the previous destruction and dispersal of his own headquarters.
Klopper decided that a stand would be made in the western area of the fortress on the ground still held by South African troops who had not been seriously attacked. By 2000hrs he had changed his mind and concluded that an effective defence was impossible. He signalled to all units that they should prepare for a mass breakout starting during the night. This order was given to mobile troops at around 0200hrs the next day and some transport attempted to get out of the fortress and away to the west. Those without transport, which
Escape From Tobruk.
Between 0500hrs and 0600hrs that morning Maj. Gen. Klopper changed his mind and decided that little could now be achieved through further prolonged resistance. A short time later he sent out an officer to contact the enemy and ask for terms. By mid-morning orders had been received by all units to cease firing and to lay down their arms. Tobruk had surrendered. The fortress that had previously withstood siege for seven months had resisted for just one day. This order was received with general amazement by many and disbelief by a few. The 2nd/7th Gurkha rifles and the 2nd Cameron Highlanders refused to surrender and fought on, with the Gurkhas resisting enemy attempts to stop them until 22 June. Another group of 199 men from the 2nd Coldstream Guards, led by Maj. Sainthill, fought their way out and escaped back to Egypt, collecting a further 188 stragglers from other units along the way. Another small party of the Kaffrarian Rifles trekked along the coast on foot, dodging parties of Germans and Italians to reach the British lines at El Alamein 38 days later.
The loss of Tobruk  was a great disaster for the British; over 33,000 British, South African, Indian and native troops were taken into captivity along with vast amounts of stores, fuel and ammunition. So swift was the collapse that the planned destruction of these supplies could not be put into operation. Most discouraging was that over 2,000 serviceable vehicles were seized and put into use by the Axis forces. Nor was the disaster just measured in human and material terms, the blow to British and South African pride and morale was incalculable - South Africa had lost a third of all its forces in the field.
Winston Churchill was in Washington when news of the surrender reached him, humiliating handed over whilst in a meeting with President Roosevelt. He felt that it was one of the heaviest blows he had received during the war. Further embarrassment was heaped upon him when a motion expressing no confidence in the direction of the war was tabled in the House of Commons. The mood of the nation was at a very low ebb.
The gloom that descended over Eighth Army was in great contrast to the pride and triumph felt by all of Rommel's Panzerarmee Afrika. Recognition and admiration for this victorious force and its charismatic commander rang around the world. In Berlin, Rommel's bold and devastating conquest of the whole of Libya and the thrashing of Eighth Army led to his immediate promotion to Generalfeldmarschall. He instantly became Germany's most famous and successful general. He now looked for further triumphs and another clash with British Eighth Army in Egypt.
 Maj. Gen. H. B. Klopper; in command of all forces within the perimeter. Klopper was a general with little battle experience who had come from a training command to take over the 2nd South African Division just one month previously. At his first conference with his subordinates on 18 June, Klopper declared that Tobruk would be held as part of Eighth Army's wider plan and he asked them to be prepared for a siege of at least three months. Klopper proved to be a headstrong individual who chose to ignore the advice of his more experienced junior commanders on a number of important matters regarding the defence of Tobruk, including those of Brigadier Willison who, had served through the earlier siege as commander of the garrison's reserve.
 The Tobruk of June 1942 was not the same fortress that had endured the long siege of the previous year; its defences were in a very poor state. The neglect was caused by a number of factors, the most significant of which was Auchinleck's February decision that it was not to be held if surrounded. The success of the Crusader offensive the previous winter and its use as a major supply base for the proposed spring offensive into Tripolitania all diverted attention away from regarding the port area as a stronghold. Many of its protective minefields and wire had been cleared for use in the Gazala Line and some of the anti-tank ditches around the perimeter had collapsed or been filled in. Now, with the suddenness of Rommel's advance and the breakdown of Eighth Army's protective screen, Tobruk was again in the front line and its long 48km perimeter was in great need of its fortress reputation.
The troops garrisoning Tobruk were drawn from a variety of formations and consisted of two brigades from the 2nd South African Division, the 201st Guards Motor Brigade Group and the 11th Indian Brigade, together with the 61 Valentine and Matilda infantry tanks of the 32nd Army Tank Brigade. Despite having two landing grounds within the defences, there were no aircraft available, nor were there very many anti-aircraft guns with which to deter the Luftwaffe. One thing that was in abundance, however, was the enormous quantity of supplies. There were three million rations to sustain the 35,000 men of the garrison, along with 7,000 tons of water, one and a half million gallons of fuel and nearly 300,000 rounds of field, medium, antitank and anti-aircraft ammunition for the three field regiments, two medium regiments, one anti-tank battery and one anti-aircraft battery of artillery within the defences.