D-Day Landing Deceptions
In the run up to the D-Day landings in Normandy, the Western Allies devised a multifaceted plan to deceive the Germans about the timing and location of their planned invasion of Europe in 1944. The deception aimed to conceal the actual time and date of the invasion, convince the Germans that the main invasion would land in the Pas de Calais, and keep the Germans from shifting troops from the Pas de Calais to Normandy. They wanted to achieve this by convincing them that the Normandy landings were diversionary, intended to draw defenders from the Pas de Calais in order to weaken it for the main invasion.
A major component of the deception was Operation Fortitude South, which created a fictitious “First US Army Group” (FUSAG) in southeast England opposite the Pas de Calais, under the command of general George S. Patton. Allied intelligence sold the fake army group’s existence to the Germans with fake radio traffic between fictitious FUSAG units. The process was successful by allowing German air reconnaissance to fly over and photograph concentrations of FUSAG tanks and transports that were actually inflatable dummies, and feeding German intelligence fake reports via double agents and turned spies about FUSAG’s intentions to invade the Pas de Calais. A subsidiary, Fortitude North, created a fictitious British Fourth Army in Scotland, and convinced the Germans that it planned to invade Norway so as to tie down the German divisions there.
After D-Day, the Allied deception plan successfully kept the Germans from committing fully to a counter attack by convincing them that the Normandy landings were not the main event, but the first in a series of landings. The German high command was thus led to keep units guarding other potential landing sites, mainly the Pas de Calais which was threatened by the fictitious FUSAG under Patton, instead of sending them to reinforce the Normandy defenders.
The deception succeeded beyond the Allies’ wildest expectations. Intelligence planners had hoped to convince the Germans to stay put in the Pas de Calais for two weeks after D-Day, rather than immediately send the units there to reinforce Normandy. Instead, the deception worked so well that the Germans stayed put in the Pas de Calais not just for the hoped-for two weeks, but for seven. The breathing space bought the Allies time to strengthen their Normandy beachhead to not only withstand German counterattacks, but to break out of Normandy in July and rapidly sweep through France, whose liberation was largely completed by September, with rampaging Allied armies that finally halted at the German border after running out of fuel.