The massive buildup of troops, armaments, and supplies on British soil posed a formidable security problem for the Allies. As Allied Lieutenant General Morgan said in the spring of 1944, "If the enemy obtains as much as forty-eight hours warning of the location of the assault area, the chances of success are small, and any longer warning spells certain defeat." (1) To keep the Germans guessing about invasion plans, the Allies created an elaborate deception plan code-named Operation Fortitude.
Fortitude's objective was to convince the Germans that the Allied offensive would begin with the invasion of southern Norway. Then, in about the third week of July, the main attack would be launched against the Pas de Calais, the point closest to England and the most likely landing spot. The Allies used every means possible to promote these perceptions and to confuse German intelligence.
General George S. Patton, well known among the Germans, was assigned to command a fictitious 1st Army Group across the Channel to Calais. Here the fake landing craft, wooden tanks, and other material were massed in open fields and along the coast--and left to be photographed by German reconnaissance planes. To enhance the suspicion that Patton's "forces" would lead the invasion, no press reports about Patton's whereabouts or actions were allowed.
The Germans were constantly monitoring radio traffic around Great Britain, and could locate the position of powerful Allied transmitters. To counter this, bogus radio transmissions from Patton's 1st Army Group simulated the frenzied activity of a pre-invasion force. Transmissions from the 21st Army Group, an actual U.S. invasion army, were re-routed across ground wires and broadcast from the south to further confuse the enemy.
Air attacks on targets in the months before the invasion could easily have tipped off the Germans to the Normandy location. Thus, for every target attacked near Normandy, two were attacked elsewhere--in particular, targets near the Pas de Calais.
Even after D-Day, the belief was encouraged that the attack on Normandy was a diversionary one, and that the main thrust would come at Calais. This ruse proved invaluable in delaying Hitler's decision to send reinforcements to the armies defending Normandy.
While Operation Fortitude successfully confused the Germans, extreme security measures were taken to ensure that the true Overlord plans, known by more officers and troops every day, remained secret. As the invasion approached, all troops were forbidden any contact with the world outside their camps. Their vast encampments in southern England were surrounded with barbed wire and armed guards. Men were not allowed to send letters or bid farewell to their girlfriends or families. No visitors were allowed. Civilians who accidentally wandered into restricted areas were detained. Their families were told that they were well--but would be unable to return home for some time. (2)
Many of the troops who were confined to their camps during the last days and took part in the final push for victory never came home at all. But there can be no doubt that the security measures and the deception of Operation Fortitude made it possible for many more to return home in victory.
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1. Warren Tute, "D-Day," (New York: MacMillan Publishing Company, 1974), p. 83.
2. Michael Wright, ed., "The Reader's Digest Illustrated History of World War II: The World at Arms," (New York: The Reader's Digest Association, 1989), p. 297.
