For two months, Gen Archibald Wavell, commander of British Forces in the Middle East, had watched the slow buildup of more than 140,000 Italian men and their supplies around Sidi Barrani since its capture in September. Gen Wavell could not lose Egypt and the Suez Canal, and he was grossly outnumbered with only 36,000 troops. So he decided to attack.
On 8 December, 1940, troops of the Maj Gen Richard O’Conner’s Western Desert Force, the Red Eagles of the 4th Indian Division and the Desert Rats of the British 7th Armored Division, moved into assault positions for what they thought was another training exercise. They had been training all week on what they didn’t know were exact mock ups of Italian positions around Sidi Barrani that were identified by the Long Range Desert Group. In the morning of 9 December, Wavell launched Operation Compass. Initially, British and Indian artillery bombarded the Italian base camps also id’d by the LRDG. Later that morning, the Western Desert Force attacked.
The Italian defense was completely surprised and almost immediately collapsed. In three days, the British overran the Italian camps around Sidi Barrani and took over 38,000 prisoners, suffering just 650 casualties.