"The Allies used double-agents to feed information back to their German controllers. Elaborate tricks suggested the Allies might invade across the narrowest part of the English Channel, at the Pas de Calais, or through Gibraltar, and even Norway. Three agents, known as ‘Garbo’, ‘Brutus’ and ‘Tricycle’ were particularly valuable as they were well-trusted by their German controllers.

Backing up the spies' stories were fake armies. The most important of these was the hoax 1st U.S Army Group in Kent, which was placed under the command of U.S General George Patton.

Roads and fields were lined with dummy tanks, trucks and aircraft. Fake landing craft were placed along the southeast coast of England. German Luftwaffe planes were occasionally allowed to fly over to take aerial photographs. The Allies also simulated the radio communications that would be expected for such a group. Nearer the time of the invasion the Allies dropped twice as many bombs on the Pas de Calais as they did on Normandy.

Even on D-Day itself, Allied planes dropped dummy paratroopers and tin foil to confuse German radar and maintain the idea the invasion would come further north. The real invasion plans were kept top secret, with only the most senior British and American commanders in the know.

Movement in the south of England was restricted in the months leading up to D-Day, with a coastal strip up to 50 miles deep in places out of bounds to all but authorised personnel. Intercepted German transmissions showed that when it came, the Germans were still thoroughly confused as to the time and place of the actual invasion."