Tobruk attacked as the British force collapses in June 1942

Rommel planned a quick attack to capture the Tobruk fortress. The attack by the German Africa Corps hit the southeast sector of Tobruk. They used only forty tanks with accompanying infantry. Tobruk was no longer defended by the seasoned crew that had mounted a credible defense in 1941. Instead, they had a temporary force commanded by a South African. The pre-attack softening up came with dive bombers and artillery fire. The tanks easily broke through the defense line and broke through to the defending guns. By "early afternoon" they hit the harbor with guns firing from the escapment. They had taken the harbor by evening. The garrison commander, Major-General Klopper surrendered when the defenders were totally defeated. They took some 35,000 prisoners, four "infantry brigadiers", and a tank brigade.
The Australian historian says that there were more than one hundred tanks were in the attack that captured Tobruk. Veterans of the 1941 Tobruk defense debated the defensive arrangements that had failed in 1942. Apparently, in June 1942, the enemy attacked on  broad front and the defense was too slow to bring reserves forward. The defenders were also not prepared to defend against a large tank attack. That alone was enough to succeed.
Once Tobruk fell, the Eighth Army withdrew to Mersa Matruh. Rommel continued to use infiltration tactics against the British who were not able to cope with the speed of his movements. Rommel was up on them by 25 June 1942. That forced Auchinleck's hand and he relieved General Ritchie of command and took over as Eighth Army commander. That was apparently what Mr. Churchill had wanted for some time.
X Corps had responsibility for holding Mersa Matruh. They had the 10th Indian Division and 50th Division. General Gott, now a Lieutenant-General, commanded XIII Corps. He held the left. He had the remainder of the armored divisions and a newly configured New Zealand Divisiion. They were now motroized but with just two brigades. XXX Corps was back at El Alamein, over a hundred miles away. This is based on the account in Vol.III of the Australian Official History.