Personal/Equipment Trickery
Making sure the Germans had no idea when or where the attack came was a remarkable story. Decoy British landing craft and inflatable rubber trucks were deployed to simulate a build-up of forces for the fake Channel crossing in the Pas de Calais area. The Allied deceptions succeeded in forcing Field Marshal Erwin Rommel to heavily fortify Pas de Calais.
Thousands of men and women were involved, but perhaps the most important, and certainly the most dramatic, were the dozen or so members of BI, the counterespionage arm of MI-5, the British internal-security agency. Using a variety of sources, such as code-breaking and interrogation of captured agents, the British caught German spies as they parachuted into England or Scotland. Sir John Masterman, head of BI, evaluated each spy. Those he considered unsuitable were executed or imprisoned. The others were "turned"-made into double agents who sent radio messages in Morse code to German intelligence, the Abwehr. Each spy had his own distinctive "signature" in the way he used the code's dots and dashes, which was immediately recognizable by the German spy master receiving the message. The Brits kept the double agents tap-tap-tapping, but only what they were told to send out.
Operation Double-Cross, which began in the dark days of 1940, managed to locate and turn every German spy in the United Kingdom-some two dozen in all. From the beginning the British aimed it exclusively toward the moment when the Allies returned to France. Building this asset over the years required feeding the Abwehr information that was authentic, new and interesting, but either relatively valueless or something the Germans were bound to learn anyway. The idea was to make the agents trustworthy and valuable in the eyes of the Germans, then spring the trap on D-Day, when the double agents would flood the Abwehr with false information.
The first part of the trap was to make the Germans think the attack was coming at the Pas de Calais. The Germans already anticipated that this was where the Allies would come ashore, so it was only necessary to reinforce their preconceptions. The Pas de Calais was indeed the obvious choice. On the direct London-Ruhr-Berlin line, it was near Antwerp, Europe's best port. Inland the terrain was flat, with few natural obstacles. At the Pas de Calais the Channel was at its narrowest, giving ships the shortest trip and British-based fighter aircraft much more time over the invasion area.
Because the Pas de Calais was the obvious choice, the Germans put their strongest fixed defenses there, backed up by the Fifteenth Army and a majority of the panzer divisions in France. Whether or not they succeeded in making the position impregnable we will never know, because Supreme Allied Commander Dwight Eisenhower decided not to find out. He chose Normandy instead. Normandy had advantages, including the port of Cherbourg, the narrowness of the Cotentin Peninsula, access to the major road network at Caen and proximity to the English ports of Southampton and Portsmouth. Normandy's greatest advantage, however, was that the Germans were certain to consider an attack there highly unlikely, because it would be an attack in the wrong direction: Instead of heading east, toward the German heartland, the Allies would be heading south into central France.
The second part of the trap was to make the Germans think that Normandy was a feint even after the attack began. Here geography also reinforced Eisenhower's choice: If there were major Allied landings at the Pas de Calais, Hitler would not keep troops in Normandy for fear of their being cut off from Germany. But he might be persuaded to keep troops in the Pas de Calais following a landing in Normandy, because they would still stand between the Allied forces and Germany.
The deception plan, code-named Fortitude, a joint BritishAmerican venture, made full use of Double-Cross, dummy armies, fake radio traffic and elaborate security precautions. Fortitude was a tremendous undertaking which was designed to make the Germans think the attack might come at the Biscay coast, in the Marseilles region or even in the Balkans. Most important were Fortitude North, which set up Norway as a target (the site of Hitler's U-boat bases, essential to his offensive operations), and Fortitude South, with the Pas de Calais as the target.
To get the Germans to look toward Norway, the Allies had to convince them that Eisenhower had enough resources for a diversion or secondary attack. This was doubly difficult because of Ike's acute shortage of landing craft-it was touch and go as to whether there would be enough craft to carry five divisions ashore at Normandy as planned, much less spares for another attack. To make the Germans believe otherwise, the Allies used Double-Cross and Allied radio signals to create fictitious divisions and landing craft on a grand scale. The British Fourth Army, for example, stationed in Scotland and scheduled to invade Norway in mid July, existed only on the airwaves. Early in 1944 some two dozen overage British officers were sent to northernmost Scotland to spend the next months filling the air with an exact duplicate of the wireless traffic that accompanies the assembly of a real army, communicating in low-level and thus easily broken cipher. They created the impression that corps and division headquarters were scattered all across Scotland: "80 Div. request 1,800 pairs of crampons, 1,800 pairs of ski bindings," the messages read, or "7 Corps requests the promised demonstrators in the Bilgeri method of climbing rock faces." There was no Eightieth Division, no Seventh Corps.
Meanwhile, the turned German spies sent encoded radio messages to Hamburg and Berlin describing heavy train traffic in Scotland, new division patches seen on the streets of Edinburgh, and rumors among the troops about going to Norway. Wooden twin-engine "bombers" began to appear on Scottish airfields. British commandos made some raids on the coast of Norway, pinpointing radar sites, picking up soil samples (ostensibly to test the suitability of beaches to support a landing), and in general trying to look like a pre-invasion force.
Thousands of men and women were involved, but perhaps the most important, and certainly the most dramatic, were the dozen or so members of BI, the counterespionage arm of MI-5, the British internal-security agency. Using a variety of sources, such as code-breaking and interrogation of captured agents, the British caught German spies as they parachuted into England or Scotland. Sir John Masterman, head of BI, evaluated each spy. Those he considered unsuitable were executed or imprisoned. The others were "turned"-made into double agents who sent radio messages in Morse code to German intelligence, the Abwehr. Each spy had his own distinctive "signature" in the way he used the code's dots and dashes, which was immediately recognizable by the German spy master receiving the message. The Brits kept the double agents tap-tap-tapping, but only what they were told to send out.
Operation Double-Cross, which began in the dark days of 1940, managed to locate and turn every German spy in the United Kingdom-some two dozen in all. From the beginning the British aimed it exclusively toward the moment when the Allies returned to France. Building this asset over the years required feeding the Abwehr information that was authentic, new and interesting, but either relatively valueless or something the Germans were bound to learn anyway. The idea was to make the agents trustworthy and valuable in the eyes of the Germans, then spring the trap on D-Day, when the double agents would flood the Abwehr with false information.
The first part of the trap was to make the Germans think the attack was coming at the Pas de Calais. The Germans already anticipated that this was where the Allies would come ashore, so it was only necessary to reinforce their preconceptions. The Pas de Calais was indeed the obvious choice. On the direct London-Ruhr-Berlin line, it was near Antwerp, Europe's best port. Inland the terrain was flat, with few natural obstacles. At the Pas de Calais the Channel was at its narrowest, giving ships the shortest trip and British-based fighter aircraft much more time over the invasion area.
Because the Pas de Calais was the obvious choice, the Germans put their strongest fixed defenses there, backed up by the Fifteenth Army and a majority of the panzer divisions in France. Whether or not they succeeded in making the position impregnable we will never know, because Supreme Allied Commander Dwight Eisenhower decided not to find out. He chose Normandy instead. Normandy had advantages, including the port of Cherbourg, the narrowness of the Cotentin Peninsula, access to the major road network at Caen and proximity to the English ports of Southampton and Portsmouth. Normandy's greatest advantage, however, was that the Germans were certain to consider an attack there highly unlikely, because it would be an attack in the wrong direction: Instead of heading east, toward the German heartland, the Allies would be heading south into central France.
The second part of the trap was to make the Germans think that Normandy was a feint even after the attack began. Here geography also reinforced Eisenhower's choice: If there were major Allied landings at the Pas de Calais, Hitler would not keep troops in Normandy for fear of their being cut off from Germany. But he might be persuaded to keep troops in the Pas de Calais following a landing in Normandy, because they would still stand between the Allied forces and Germany.
The deception plan, code-named Fortitude, a joint BritishAmerican venture, made full use of Double-Cross, dummy armies, fake radio traffic and elaborate security precautions. Fortitude was a tremendous undertaking which was designed to make the Germans think the attack might come at the Biscay coast, in the Marseilles region or even in the Balkans. Most important were Fortitude North, which set up Norway as a target (the site of Hitler's U-boat bases, essential to his offensive operations), and Fortitude South, with the Pas de Calais as the target.
To get the Germans to look toward Norway, the Allies had to convince them that Eisenhower had enough resources for a diversion or secondary attack. This was doubly difficult because of Ike's acute shortage of landing craft-it was touch and go as to whether there would be enough craft to carry five divisions ashore at Normandy as planned, much less spares for another attack. To make the Germans believe otherwise, the Allies used Double-Cross and Allied radio signals to create fictitious divisions and landing craft on a grand scale. The British Fourth Army, for example, stationed in Scotland and scheduled to invade Norway in mid July, existed only on the airwaves. Early in 1944 some two dozen overage British officers were sent to northernmost Scotland to spend the next months filling the air with an exact duplicate of the wireless traffic that accompanies the assembly of a real army, communicating in low-level and thus easily broken cipher. They created the impression that corps and division headquarters were scattered all across Scotland: "80 Div. request 1,800 pairs of crampons, 1,800 pairs of ski bindings," the messages read, or "7 Corps requests the promised demonstrators in the Bilgeri method of climbing rock faces." There was no Eightieth Division, no Seventh Corps.
Meanwhile, the turned German spies sent encoded radio messages to Hamburg and Berlin describing heavy train traffic in Scotland, new division patches seen on the streets of Edinburgh, and rumors among the troops about going to Norway. Wooden twin-engine "bombers" began to appear on Scottish airfields. British commandos made some raids on the coast of Norway, pinpointing radar sites, picking up soil samples (ostensibly to test the suitability of beaches to support a landing), and in general trying to look like a pre-invasion force.