As a counter-espionage measure, many of the troops involved were not informed that the operation wasn't an exercise, until they were very nearly engaged in combat. The attack was supported by 25-pounder artillery and Blenheim bombers and was centered around the advance of Mk.II Matilda tanks. Within an hour of the onset of combat, Italian General Maletti would be dead and 4,000 Italian soldiers would surrender. Within three days, 237 artillery, 73 tanks, and 38,300 soldiers would be captured. The attacking forces would move west along the Via della Vittoria, through Halfaya Pass, and capture Fort Capuzzo, Libya.
O'Connor wanted to continuing attacking, at least as far as Benghazi; however, General Wavell had ordered the 4th Indian Division to take part in an offensive against Italian forces in Abyssinia. O'Connor would state, "[This] came as a complete and very unpleasant surprise...It put paid to the question of immediate exploitation...". An Australian division replaced the Indians. The attack would eventually continue, ending with the 7th Armoured Division cutting off the Italian retreat. After 10 weeks the British would advance ~800km, destroying 400 tanks and 1,292 artillery pieces and capturing 130,000 POWs. The British would suffer 494 fatalities and 1,225 wounded. However the advance stopped short of driving the Italians out of North Africa. As the advance reached Al Argheila, Churchill ordered that it be stopped, and troops dispatched to defend Greece. A few weeks later the first troops of the German Afrika Korps would begin arriving in Tripoli (Operation Sonneblume), and the desert war would take a completely different turn. (1 - p.50)