On Tuesday 6 June, 1944, nearly 160,000 allied soldiers landed along a 50-mile stretch of coast in Normandy.

One of the most famous events of the Second World War; D-Day marked the beginning of the end for the Nazi Occupation of western Europe. But at the time, German generals in charge of defending the beaches didn’t believe the full scale Allied invasion of France had even begun.

Thanks to a series of deception efforts undertaken by the Allies, the bulk of Germany’s defensive forces were 150 miles away when the Normandy landings were taking place.

How German forces were tricked on D-Day

© IWM

Voice over: "On Tuesday the 6th of June, 1944, nearly 160,000 allied soldiers landed along a 50-mile stretch of coast in Normandy, France. One of the most famous events of the Second World War; D-Day marked the beginning of the end for the Nazi Occupation of western Europe. But at the time, the German generals in charge of defending the beaches didn’t believe the full scale Allied invasion of France had even begun. Thanks to a series of deception efforts undertaken by the Allies, the bulk of Germany’s defensive forces were 150 miles away when the Normandy landings were taking place."

Collection film footage: "The armies of the United Nations have made their first landings on the soil of Western Europe. Another of the great decisive battles of world history has been joined. This is D-Day."

Michelle Kirby: "I’m here at IWM London standing in the heart of the newly opened Spies, Lies and Deception exhibition. This part of the galleries explores how and why deception has been used in conflicts over the past century. 

The D-Day deceptions were massively successful, and today they offer us a brilliant masterclass in military misdirection.   

The aim of the D-Day deceptions was to keep German military leaders guessing about the place and time of the Allied invasion, so that the invading forces met as little opposition as possible. The hope was that this would give the Allies the maximum chance of success, saving lives in the process. Magruder’s Principle is the idea that it’s often much easier to deceive an enemy into hanging onto their pre-existing incorrect beliefs, than to trick them into changing those beliefs.  

Voice over: "The D-Day deceptions would do exactly that. Although the Germans knew an invasion was coming, they did not know where and when it would take place. Hitler believed that the most likely target was the Pas de Calais - the shortest route across the English Channel - and it was this preconception that formed the bases for the deception plan. 

Years of war had allowed for a variety of deception methods to gradually be refined and perfected by the Allies. This culminated in July 1943, when a top-secret group of military officers known as the London Controlling section began planning a huge deception operation. Codenamed ‘Operation Bodyguard’, it encompassed all aspects of deception relating to the Allied invasion of France. The initial plan outlined three key objectives: to make the Pas de Calais appear to be the main target, to mask the true date and time of the invasion, and to keep German forces in the Pas de Calais region, and elsewhere in Europe, for at least 14 days following the initial landings.  

In January of 1944, the Allies formed the First United States Army Group. Based in South-East England, it was placed under the command of General George S. Patton, one of the most well-known American generals of the war.  

German reconnaissance aircraft soon began reporting on a build-up of forces in the area, noting large convoys of tanks, and a number of landing craft gathered in harbours and estuaries all over southeast England. They also picked up Allied radio transmissions relating the Army’s movements. It could mean only one thing. The build-up of forces, and particularly General Patton’s presence in the area, meant the Allies were preparing to land in the Pas de Calais. But this was all part of the plan. In fact, the FUSAG didn’t exist at all, it was an entirely fictional army created for the sole purpose of deceiving German intelligence. The armoured convoys were made up of inflatable, dummy tanks and deliberately placed within sight of German reconnaissance aircraft. While the landing craft were actually made out of wood, canvas and empty barrels.  

Every effort was made to make the Army seem as real as possible - going so far as to create physical insignia and uniforms. This ruse was supported by the transmission of fake radio messages, and further solidified by false information fed to the Germans by a number of trusted double agents and spies." 

Michelle Kirby: "Juan Pujol Garcia was perhaps the most important double agent of the Second World War. Determined to spy for Britain, the Spaniard offered his services to German Intelligence in 1941, intending to become a double agent when he reached Britain, which eventually happened in April 1942. He was codenamed ‘Garbo’ by the British, after the famous actress Greta Garbo, as a nod to his own quite extraordinary ‘acting’ skills.   

Double agents played a crucial role in the D-Day deceptions because they were by far the most effective way of misleading the German leaders. As preparations for D-Day progressed, it became the job of Agent Garbo and the other double agents to divert attention away from the impending Normandy landings.  

To achieve this, Pujol created a fake network of 27 imaginary informants, which enabled him to send false information by radio to his Nazi handlers on all aspects of the Allied preparations. He even managed to convince them in the days immediately following D-Day, that the Normandy landings were just a ruse, intended to distract the Germans from the supposedly ‘real’ invasion target, the Pas de Calais. 

This was so successful that, for weeks after D-Day, German leaders kept forces that could have reinforced Normandy, in the Pas de Calais area, waiting to repel a non-existent second invasion." 

Voice over: "Alongside the deception efforts leading up to the invasion, were further operations during the landings themselves. These tactics aimed to keep the German defenders in the dark until the very last second, and make the invasion appear much larger and wider than it actually was." 

Collection film footage: "Enemy radar installations were either destroyed, jammed or deceived by counterfeit presentations. The contrivance of radar signals misleading to the enemy involved at least one completely novel manoeuvre." 

Michelle Kirby: "These strips of aluminium are known as Window. When dropped in large numbers from an aircraft, they reflect radar signals, producing a large blip on radar screens. In the early hours of D-Day, RAF aircrews dropped Window over the English Channel to trick the German radar operators into thinking that two large invasion fleets were heading at a speed of 8 knots towards the French coast, northeast of the Normandy beaches. They achieved this by flying repeatedly across the channel, each time dropping bundles of Window a little closer to the French coast. This required accurate navigation and precision flying that was so demanding that each aircraft had two pilots and two navigators onboard, working in shifts. The RAF’s elite Dambusters Squadron was tasked with one of these difficult operations.   

The idea was to make the German defenders believe that Allied forces were about to land in Boulogne and Fécamp, while the real invasion fleet, hidden by radar jamming equipment, was in fact heading towards Normandy."  

 Voice over: "The real invasion force was further hidden through the use of smoke screens. Once laid down by ships or aircraft, they concealed the movement of Allied troops as they approached the Normandy coast, and reduced the risk of attack from German artillery and aircraft."

Michelle Kirby: "Dummy parachutists like this one were used to deceive the German defenders. Around 400 of these dummies, nicknamed Ruperts by the British, were dropped from aircraft, in key locations behind the German coastal defences in the early hours of D-Day.  

They were typically made of hessian cloth, cord and brass eyelets, and tucked inside the pouch would be the parachute. And although they were smaller than life size, when viewed from the ground they were convincing enough. Some of the dummies were fitted with pyrotechnic devices that mimicked the sound of gunfire. It’s even been suggested that some were designed to explode on impact, to destroy the evidence. A few Special Forces men were dropped with the dummies to create more fake sights and sounds of battle.   

The aim of the operation - to draw German troops away from the landing beaches - appears to have been successful, as the German army in Normandy sent a brigade of troops to look for the parachutists inland."

Voice over: "Despite the success of the deception operations, Allied forces still faced heavy resistance when they reached the shore. The Germans were still prepared for some kind of invasion, and they had fortified the Normandy coast with bunkers, artillery, and mines. The fighting on the first day of the landings was particularly fierce and the Allies made slow progress on some beaches. Casualties were high on both sides; however, the Allies were able to achieve their objective and establish a beachhead. D-Day was a major victory, it paved the way for the liberation of France and the eventual defeat of Nazi Germany." 

Michelle Kirby: "Unsure of the time or place of the landings, the German forces were spread thinly across a wide stretch of coastline instead of being concentrated in Normandy to meet the invasion. When the Allies landed, they achieved precisely what they had been hoping for; the element of surprise. Some German Generals were slow to respond, refusing to believe that the main invasion had really begun. 

There still remained a huge amount of fighting to be done following D-Day, and many challenges to be overcome before the Normandy campaign came to a close. Allied victory was by no means assured on D-Day, but it gave them the all-important first grip on the continent they needed, and the deception efforts played a crucial role in that. 

If you want to learn more about the D-Day Deceptions, or see some of these objects for yourself – you can. Spies, Lies and Deception is IWM London’s brand-new exhibition exploring some of the most successful, surprising and shocking stories of espionage and deception from the past 100 years. From First World War dummy heads in the trenches, to Cold War spies, gadgets and more. This free exhibition is here until April 2024."

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