The 7th Armoured Division, who gained fame as the "Desert Rats," began life as a direct response to the Italian threat to the Suez Canal. In 1938, Headquarters, British Troops in Egypt, assembled at Mersa Matruh, to prepare for the expected attack by the Italian Army. This force formed the core of what was to become the 7th Armoured Division.
In September of 1940, the Italian 10th Army launched its invasion of Egypt. This posed a severe threat to the Suez Canal, a vital supply and communications route for the Allies, but British forces were far outnumbered and withdrew to Sidi Barrani. By December the British had been reinforced and struck back aggressively. The Italian 10th Army began to waver. Tobruk was captured on the 22nd of January, and the retreating 10th Army soon suffered a disastrous defeat when it was cut off at Beda Fomm.
When Rommel and the nucleus of what was to become the Afrika Korps arrived at the port of Tripoli in mid-February of 1941, no one knew that from this small beginning there would grow a serious threat to British forces in North Africa. When a German Reconnaissance Battalion captured the town of El Agheila on March 24th, 1941, the campaign in Cyrenaica had begun in earnest.
By the end of June of 1941 both sides had exhausted their strength in the failed Allied operations "Brevity" and "Battleaxe." The theater was then quiet for several months while the Germans and Italians besieged Tobruk, a vital objective for any advance into Egypt.
By November of 1941, the British had built up large stockpiles of supplies and had received numerous reinforcements. Tobruk remained under Axis siege, with Rommel hoping to assault the fortress early in the month. Each side raced to launch its attack first, but British control of the sea lanes gave them an enormous advantage. On the 18th of November, 1941, the Allied offensive known as Operation Crusader began. The Desert Rats would be heavily involved.