On this day, two British divisions, half of them composed of Indian troops, attack seven Italian divisions in Egypt. Overwhelmed, the Italian position in Egypt collapsed.
Italy had declared war on Great Britain in June. At that time, Italian General Rodolfo Graziani had almost 10 times the number of men in Libya than the British forces in Egypt under General Archibald Wavell, which were commissioned to protect the North African approaches to the Suez Canal. A vast western desert stretched between the antagonists, who sat for months without confrontation. In the meantime, Italian forces had passed into Egypt—but Britain had also reinforced its own numbers. British cryptographers were also able to break the Italian military code, enabling British commanders to anticipate Italian troop movements, size, and points of vulnerability.
British command decided to make a first strike. On December 7, armoured car patrols surreptitiously set out to determine gaps in the minefield the Italians had laid. On December 9, Major General Richard Nugent O'Connor from Mersa Matruh in Egypt launched a westward offensive. Thirty thousand Brits warred against 80,000 Italians—but the British brought with them 275 tanks against the Italians' 120. As O'Connor cut through a gap in the chain of forts the Italians had established, the British 7th Armoured Division swept along the western coast to cut off any hope of an Italian retreat. Within three days, 40,000 Italian prisoners were taken. The end of the Italian occupation of North Africa had begun.
Taken from: http://www.history.com/this-day-in-history/brits-launch-offensive-against-italians-in-north-africa [08.12.2014]