The German invasion of Norway was a dramatically daring military operation. It confronted the United States as well as Great Britain with a strategic threat. [1] A more extensive discussion of the German planning and operations appears in Earl F. Ziemke, The German Northern Theater of War, 1940-1945, Department of German Invasion Plans for the British Isles, 1940 Bodleian Lib.Hardback | Books, Comics & Magazines, Non Fiction | EBay! Adolf Hitler, 16 July 1940. Immediately after the fall of France in June 1940, Hitler ordered his generals to organize the invasion of Britain under a plan codenamed Operation Sealion. The objective was to land 160,000 German soldiers along a forty-mile coastal stretch of south-east England. The planned 1940 cross-channel invasion of Britain, Operation Sea Lion, remains German F