Operation Fortitude

Fortitude was one of the major elements of Operation Bodyguard, the overall Allied deception strategy for the Normandy landings. Bodyguard’s principal objective was to ensure the Germans would not increase troop presence in Normandy by promoting the appearance that the Allied forces would attack in other locations. After the invasion on the 6th June 1944, the plan was to delay movement of German reserves to the Normandy beachhead and prevent a potentially disastrous counter-attack. Fortitude’s objectives were to promote alternative targets of Norway and Calais.

The planning of Operation Fortitude came under the auspices of the London Controlling Section, a secret body set up to manage Allied deception strategy during the war. However, the execution of each plan fell to the various theatre commanders, in the case of Fortitude this was Supreme Headquarters Allied Expeditionary Force (SHAEF) under General Dwight D. Eisenhower.

Fortitude was split into two parts, both with similar aims. Fortitude North was intended to convince the German high command that the Allies, staging out of Scotland, would attempt an invasion of occupied Norway. Fortitude South employed the same tactic, with the apparent objective being Pas de Calais.

The first version of the Fortitude South plan was produced in early January 1943 and aimed to counter the likelihood that the Germans would notice invasion preparations in the South of England. The intention was to create the impression that an invasion was aimed at the Pas de Calais sometime in mid-July; once the real invasion had landed, six fictional divisions would keep this threat to Calais alive. The Fortitude South plan would be implemented, at an operational level, by the invasion force—the 21st Army Group under the command of General Bernard Montgomery.

For deceptions, the Allies had developed a number of methodologies, referred to as “special means”. They included combinations of physical deception, fake wireless activity, leaks through diplomatic channels, and double agents. Fortitude used all of these techniques to various extents. For example, Fortitude North relied heavily on wireless transmission (the Allies thought that Scotland was too far for German reconnaissance to reach) while Fortitude South utilised the Allies network of double agents.

  • Physical deception: to mislead the enemy with non-existent units through fake infrastructure and equipment, such as dummy landing craft, dummy airfields, and decoy lighting.
  • Controlled leaks of information through diplomatic channels, which might be passed on via neutral countries to the Germans.
  • Wireless traffic: To mislead the enemy, wireless traffic was created to simulate actual units.
  • Use of German agents controlled by the Allies through the Double Cross System to send false information to the German intelligence services.
  • Public presence of notable staff associated with phantom groups such as FUSAG, most notably the well-known US general George S. Patton.

One of the main deception channels for the Allies was the use of double agents. B1A (the Counter-Intelligence Division of MI5) had done a good job intercepting all of the German agents in Britain. Many of these were recruited as double agents under the Double Cross System. The three most important double agents during the Fortitude operation were:

Juan Pujol García (Garbo), a Spanish citizen who managed to get recruited by German intelligence, and sent them abundant but convincing disinformation from Lisbon, until the Allies accepted his offer and he was employed by the British. He created a network of 27 imaginary sub-agents by the time of Fortitude, and the Germans unwittingly paid the British Exchequer large amounts of money regularly, thinking they were funding a network loyal to themselves. He was awarded both the Iron Cross by the Germans and an MBE by the British after D-Day.

Roman Czerniawski (Brutus), a Polish officer who ran an intelligence network for the Allies in occupied France. Captured by the Germans, he was offered a chance to work for them as a spy. On his arrival in Britain, he turned himself in to British intelligence.

Fortitude North was designed to mislead the Germans into expecting an invasion of Norway. By threatening any weakened Norwegian defence the Allies hoped to prevent or delay reinforcement of France following the Normandy invasion. The plan involved simulating a build-up of forces in northern England and political contact with Sweden.

During a similar operation in 1943, Operation Cockade, a fictional field army (British Fourth Army) had been created, headquartered in Edinburgh Castle. It was decided to continue to use the same force during Fortitude. Unlike its Southern counterpart, the deception relied primarily on “Special Means” and fake radio traffic since it was judged unlikely that German reconnaissance planes could reach Scotland un-intercepted. False information about the arrival of troops in the area was reported by double agents Mutt and Jeff, who had surrendered following their 1941 landing in the Moray Firth, while the British media cooperated by broadcasting fake information, such as football scores or wedding announcements, to non-existent troops. Fortitude North was so successful that by late spring 1944, Hitler had thirteen army divisions in Norway.

In the early spring of 1944, British commandos attacked targets in Norway to simulate preparations for invasion. They destroyed industrial targets, such as shipping and power infrastructure, as well as military outposts. This coincided with an increase in naval activity in the northern seas and political pressure on neutral Sweden.

Fortitude South

Fortitude South employed similar deception in the south of England, threatening an invasion at Pas de Calais by the fictional 1st U.S. Army Group (FUSAG). France was the crux of the Bodyguard plan; as the most logical choice for an invasion, the Allied high command had to mislead the German defences in a very small geographical area. The Pas de Calais offered a number of advantages over the chosen invasion site, such as the shortest crossing of the English Channel and the quickest route into Germany. As a result, German command, particularly Rommel, took steps to heavily fortify that area of coastline. The Allies decided to amplify this belief of a Calais landing.

Montgomery, commanding the Allied landing forces, knew that the crucial aspect of any invasion was the ability to enlarge a beachhead into a full front. He also had only limited divisions at his command, 37 compared to around 60 German formations. Fortitude South’s main aims were to give the impression of a much larger invasion force (the FUSAG) in the South-East of England, to achieve tactical surprise in the Normandy landings and, once the invasion had occurred, to mislead the Germans into thinking it a diversionary tactic with Calais the real objective.

The key element of Fortitude South was Operation Quicksilver. It entailed the creation of the belief in German minds that the Allied force consisted of two army groups, 21st Army Group under Montgomery (the genuine Normandy invasion force), and 1st U.S. Army Group (FUSAG) (a fictitious force under General George Patton), positioned in southeastern England for a crossing at the Pas de Calais.

At no point were the Germans fed false documents describing the invasion plans. Instead, they were allowed to construct a misleading order of battle for the Allied forces. To mount a massive invasion of Europe from England, military planners had little choice but to stage units around the country with those that would land first nearest to the embarkation point. As a result of FUSAG’s having been placed in the south-east, German intelligence would deduce that the centre of the invasion force was opposite Calais, the point on the French coast closest to England and therefore a likely landing point.

To facilitate this deception, additional buildings were constructed; dummy aircraft and landing craft were placed around possible embarkation points. Patton paid many of these a visit along with a photographer. It is thought that the Army encouraged the idea that these dummies were used to draw attention away from some of the other means of deception, such as turned agents.[21] In any case, the Allies overestimated the Germans’ abilities to conduct aerial surveillance, so many of the props were never constructed. Patton was photographed visiting the props that were mocked up on regular occasions.

A deception of such a size required input from many organisations, including MI5, MI6, SHAEF via Ops B, and the armed services. Information from the various deception agencies was organized by and channelled through the London Controlling Section under the direction of Lieutenant-Colonel John Bevan.

Fortitude South II

On 20 July Ops (B) took over control of Fortitude South from R Force. Earlier in the previous month, they had begun work on a follow up to the operation. Their new story centred on the idea that Eisenhower had decided to defeat the Germans through the existing beachhead. As a result, elements of FUSAG had been detached and sent to reinforce Normandy and instead a second, smaller, Second American Army Group (SUSAG) would be formed to threaten the Pas-de-Calais.

The plan met some criticism; first of all, there was opposition to the creation of so many fictional US formations in the face of a known manpower shortage in America. Secondly, the plan reduced the threat to Pas-de-Calais and so the Fifteenth Army might be moved to reinforce Normandy. As with its predecessor, in late June Strangeways re-wrote the operation to ensure the focus remained on Calais.

By 28 September 1944 the Allies had agreed to end the Fortitude deception, moving to operational deceptions in the field under the overall charge of Ops (B).

The Allies were able to judge how well Fortitude was working thanks to Ultra, signals intelligence obtained by breaking German codes and cyphers. On June 1st a decrypted transmission by Hiroshi Ōshima (the Japanese ambassador) to his government recounting a recent conversation with Hitler confirmed the effectiveness of Fortitude.

They maintained the pretence of FUSAG and other forces threatening Pas de Calais for some considerable time after D-Day, possibly even as late as September 1944. This was vital to the success of the Allied plan since it forced the Germans to keep most of their reserves bottled up waiting for an attack on Calais that never came, thereby allowing the Allies to maintain and build upon their marginal foothold in Normandy.

During the course of Fortitude, the almost complete lack of German aerial reconnaissance, together with the absence of uncontrolled German agents in Britain, came to make physical deception almost irrelevant. The unreliability of the “diplomatic leaks” resulted in their discontinuance. The majority of deception was carried out by means of false wireless traffic and through German double agents. The latter proved to be by far the most significant.

Reasons for success

The operation was successful for several reasons:

The long term view was taken by British Intelligence to cultivate double agents as channels of disinformation to the enemy.

The use of Ultra decrypts of machine-encrypted messages between the Abwehr and the German High Command, which quickly indicated the effectiveness of deception tactics. This is one of the early uses of a closed-loop deception system. The messages were usually encrypted by Fish rather than Enigma machines.

R.V. Jones, the Assistant Director Intelligence (Science) at the British Air Ministry insisted for reasons of tactical deception that for every radar station attacked within the real invasion area, two were to be attacked outside it.

The extensive nature of the German Intelligence machinery, and the rivalry amid the various elements.

General George S. Patton was the leader the Germans feared the most, and they considered him the Allies’ best general. Therefore, the German High Command believed he would lead the attack.

Ben Davidson

Hello, I have been studying all aspects of history for about 25 years. I have a BA History from the University of Bedfordshire. My historical areas of interest are anything really, but I specialise in 19th - 20th century Britain, America and Ireland. I am also strongly aligned with most military history, really enjoying WW2 and the US Civil War. Chuck in the king or queen and Bob's your uncle.

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