The British doubted Admiral François Darlan's promise not to allow the French fleet at Toulon to fall into German hands by the wording of the armistice conditions. They feared the Germans would seize the French Navy's fleet, docked at ports in Vichy France and North Africa and use them in an invasion of Britain (Operation Sea Lion). Within a month, the Royal Navy attacked the French naval forces stationed in North Africa in the Attack on Mers-el-Kébir. The British Chiefs of Staff Committee had concluded in May 1940 that if France collapsed, "we do not think we could continue the war with any chance of success" without "full economic and financial support" from the United States. Churchill's desire for American aid led in September to the Destroyers for Bases agreement that began the wartime Anglo-American partnership.