Britain's Naval Intelligence Division first proposed a commando raid on the dock in late 1941. When the was declared operational in January 1942, the Royal Navy (RN) and Royal Air Force (RAF) were already drawing up plans to attack her. Planners from Combined Operations Headquarters were looking at potential scenarios if "Tirpitz" escaped the naval blockade and reached the Atlantic. They decided the only port able to accommodate her was St Nazaire, especially if, like "Bismarck", she was damaged en route and needed repairs. They came to the conclusion that if the dock at St Nazaire were unavailable, the Germans were unlikely to risk sending "Tirpitz" into the Atlantic.