From early 1941, Dudley Clarke commanded the 'A' Force, based in Cairo, Egypt, which developed much of the war's Allied deception strategy. In an initial deception failure from which Clarke derived an important lesson he put to use in the future, the British intended to retake British Somaliland by an advance from Sudan into Eritrea. Operation Camilla was intended to deceive the Italians occupying British Somaliland into thinking the British intended to retake British Somaliland by an amphibious assault from Aden. Instead of moving their troops to meet the potential amphibious landing, or retreating to Italian-occupied Somalia, the Italians withdrew into Eritrea. As a result, they possessed greater strength at the British objective when the genuine British attack occurred. Clarke's lesson was to focus deception not on what the enemy should think is happening but what the deception planner wants the enemy to do as a result.