an instructor at the Staff College, but his memory was faulty; Montgomery left the Staff College in 1929, and Dempsey did not arrive until 1930. Unlike a division, which had a set structure, a corps was a flexible formation to which divisions and brigades were assigned as necessary. When he arrived in Cairo, Dempsey found all he commanded was a headquarters, because the long lines of communication to Eighth Army's spearhead could only sustain two corps (Horrocks's X Corps and Lieutenant-General Oliver Leese's XXX Corps). Dempsey was therefore employed in the planning of the Allied invasion of Sicily. The overall plan was developed by a staff in Algiers known as Force 141, under Major-General Charles Gairdner. Dempsey temporarily assumed the role of chief of staff of Force 545, the staff responsible for planning the British Eighth Army's part in the operation, until Major-General Francis de Guingand, the Eighth Army chief of staff, could be spared to take over. Dempsey did not like the plan, which involved separate, dispersed landings. This assumed that the German and Italian response would be slow and weak, and nothing in the British Army's experience of the war thus far supported the expectation that this would be the case. Dempsey wanted the Allied forces to land where they could support each other in the event that a strong and vigorous German response developed. Dempsey took his objections to Montgomery on 13 March 1943, and then to Gairdner five days later. The former agreed with him but the latter did not. De Guingand took over on 17 April, enabling Dempsey to return to command of XIII Corps. De Guingand discussed the plan with Dempsey, agreed with Dempsey's objections, and prepared an appreciation for Montgomery. Montgomery raised their objections with General Harold Alexander, the 15th Army Group commander, on 24 April. After some debate, the Supreme Allied Commander, General Dwight D. Eisenhower accepted Montgomery's revised plan on 3 May. For the invasion of Sicily, Dempsey's XIII Corps had two infantry divisions, the 5th Division under Berney-Ficklin and the 50th Division under Major-General Sidney Kirkman, and Brigadier John Cecil Currie's 4th Armoured Brigade, which had only two armoured regiments, the 44th Royal Tank Regiment and the 3rd County of London Yeomanry (Sharpshooters). He was also responsible for the 1st Airborne Division, under Major-General George Hopkinson, which would be dropped by parachute and glider just prior to the amphibious landings.