Operation Fortitude

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Operation Fortitude
Part of Operation Bodyguard
Grayscale map of Europe with the subordinate plans of Operation Bodyguard labelled
Fortitude North and South constituted the main portion of the overall Bodyguard deception
Operational scopeMilitary deception
United Kingdom
PlannedDecember 1943 – March 1944
Planned byLondon Controlling Section, Ops (B), R Force
TargetAxis powers
DateMarch – June 1944

Operation Fortitude was the code name for a World War II military deception employed by the Allied nations as part of an overall deception strategy (code named Bodyguard) during the build-up to the 1944 Normandy landings. Fortitude was divided into two sub-plans, North and South, with the aim of misleading the German High Command as to the location of the invasion.

Fortitude had evolved from plans submitted by Noel Wild, head of Ops (B), and John Bevan, from the London Controlling Section in late 1943. Early revisions in January 1944 suggested a fictional build up of troops in southern England with the hope of drawing German attention to the Calais region. Colonel David Strangeways, head of Montgomery's R Force deception staff, was unimpressed with the approach. Strangeways was widely critical of the original plan and eventually re-wrote the Fortitude deception with a focus on creating a more realistic threat.

Both Fortitude plans involved the creation of phantom field armies (based in Edinburgh and the south of England) which threatened Norway (Fortitude North) and Pas de Calais (Fortitude South). The operation was intended to divert Axis attention away from Normandy and, after the invasion on 6 June 1944, to delay reinforcement by convincing the Germans that the landings were purely a diversionary attack.


Fortitude was one of the major elements of Operation Bodyguard, the overall Allied deception stratagem for the Normandy landings. Bodyguard's main objective was to ensure the Germans would not increase troop presence in Normandy and to do so by promoting the appearance that the Allied forces would attack in other locations. It consisted of a wide range of deceptions ranging across the European front, with Operation Fortitude representing the main effort to misdirect Oberkommando der Wehrmacht (German High Command) belief in specific mainland invasion objectives.

The problem facing the Allies was that France was the most logical choice for an invasion into mainland Europe. Therefore the Allied high command had only a small geographical area across which to mislead the German defences. 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 37 divisions at his command, compared to around 60 German formations. This meant that any deception would have to convince the German high command that the Allies were not committing their full forces into Normandy and therefore hold many of those formations in reserve.[1] After the landings, there would then need to be some way to delay the movement of German reserves to the Normandy beachhead preventing a potentially-disastrous counterattack.[2][3]

Operation Fortitude focused on creating invasion threats from the United Kingdom into various parts of western Europe. The plan was eventually split into two parts, North and South. Fortitude South would focus on creating confusion about the Allied channel crossing whilst Fortitude North, staged out of Scotland, would introduce a threat to occupied Norway.[2] Planning for Bodyguard overall came under the auspices of the London Controlling Section (LCS), a secret body that was set up to manage Allied deception strategy during the war. However, the execution of individual plans fell to the various theatre commanders. In the case of Fortitude, it was Supreme Headquarters Allied Expeditionary Force (SHAEF) under General Dwight Eisenhower and specifically 21st Army Group (the invasion force) under the command of General Bernard Montgomery. A special section, Ops (B), was established at SHAEF to handle Fortitude and Montgomery formed R Force under his command to handle the tactical elements of deception.[note 1][3]

Deception techniques[edit]

Juan Pujol Garcia, or agent Garbo, was key part of the Fortitude deception

The idea of creating fake formations as a method of deception had been pioneered in Cairo by Dudley Clarke's 'A' Force earlier in the war. Fortitude made heavy use of Clarke's techniques for inflating the size of an army. It used a number of methodologies which had come to be referred to as "special means". This included combinations of physical deception, fake wireless (radio) activity, leaks through diplomatic channels or double agents, and the usage of notable officers in fake formations.

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 in intercepting numerous German agents in Britain. Many of these were recruited as double agents under the Double Cross System. For Fortitude Operation the intelligence agencies made particular use of three agents;

  • Juan Pujol García (Garbo), a Spanish citizen who volunteered to set himself up as a double agent. 'Garbo' was a key agent for the Fortitude deception. His fictional network of 27 agents across Britain was an excellent way to create the impression of additional formations. García was so trusted he was awarded the Iron Cross (for his efforts on D-Day he was awarded an MBE).
  • 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.
  • Dušan Popov (Tricycle), a Yugoslav lawyer, whose flamboyant lifestyle covered his intelligence activities.


Detailed planning ostensibly sat with Noel Wild and his Ops (B) staff. In practice it was a collaboration between Wild and the heads of the London Controlling Section and B1a. Work began in December 1943 under the codename Mespot. Wild's first version of the Fortitude plan was socialised in early January 1943 with SHAEF, political leaders and the staff officers of the 21st Army Group.[4] This iteration aimed to take advantage of the likelihood that the Germans would notice invasion preparations in southern England.[5] Wild wanted to create the impression that an invasion was aimed at the Pas-de-Calais slightly later in the year (July instead of June). Once the real invasion had landed, six fictional divisions would then keep the threat to Calais alive.[6]

Colonel David Strangeways, head of Montgomery's R Force, raised concerns about the entire plan.[4] Strangeways argued that the plan aimed to cover the Allies' real intentions instead of creating a realistic threat to Calais to which Axis forces would have to respond in defence.[6][7] He was concerned the Germans may well be aware of the Allied readiness in the South of England. Therefore they would be alert to the risk of an invasion in early June, but would realise this gave them several weeks to defeat any bridgehead and return to the defence of Calais.[7] On 25 January, Montgomery's Chief of Staff, Francis de Guingand, sent a letter to the deception planners that included asking them to focus on Pas-de-Calais as the main assault. It was almost certainly sent at the behest of Strangeways.[8] With those criticisms in hand, Wild produced his final draft for Fortitude. In the revised plan, issued on 30 January and approved by the Allied chiefs on 18 February, fifty divisions would be positioned in Southern England to attack Pas de Calais.[6][8] After the real invasion had landed, the story would change, suggesting to the Germans that several assault divisions remained in England that were ready to conduct a cross-channel attack once the Normandy beachhead had drawn German defences away from Calais. The plan still retained some of its initial form, most notably since the first part of the story still aimed to suggest an invasion date of mid-July.[9] At this point Winston Churchill judged 'Mespot' to be an unsuitable name and so 'Fortitude' was adopted from an alternative list on February 18.[note 2][4]

Strangeways rewrite[edit]

I rewrote it entirely. It was too complicated, and the people who made it had not never done it before. Now they did their best – but it didn't suit the operation that Monty was considering.... You see so much depended on the success of that deception plan.

— Strangeways, writing in 1996[10]

Strangeways was still unimpressed with the Fortitude outline and, according to Ops(B)'s Christopher Harmer, in mid-February he set out to ride "roughshod over the established deception organization".[6] Harmer writes that Strangeways displayed the same arrogance as his commanding officer; Montgomery was famously opinionated, and held a low opinion of the London establishment of the "old boys'" of Ops (B) and the LCS. More importantly, however, he had worked under Dudley Clarke in Cairo during the early war and had extensive experience of deception operations. In North Africa he had learned Clarke's maxim that deception relied on getting the enemy to do something not just think something and it was on this that his criticism focused.[4][11] He pointed out that convincing the Germans of so many fictional divisions would be tough and that even that would be easier than convincing them of Montgomery's ability to manage two entire invasions at the same time.[12] Wild's plan outlined ten divisions for the Calais assault, six of them fictional and the remainder being the real American V Corps and British I Corps. However, the corps would be part of the actual Normandy invasion and so it would be difficult to imply Calais being the main assault after D-Day.[13] Strangeways's final concerns related to the effort required for physical deception, as the plan called for large numbers of troop movements and dummy craft.[12]

Symbol of the fictional 1st US Army Group, a core element of Strangeway's plan

Strangeways's objections were so strong, and having responsibility for the plan's implementation, he refused to undertake most of the physical deception. A power struggle ensued throughout February and early March, between Ops(B) and Strangeways as to who had authority to implement each part of the deception plan. Montgomery put his full support behind his head of deception and so Strangeways prevailed.[14][15] Finally, in a 23 February meeting between R Force and Ops(B), Strangeways tore up a copy of the plan, declaring it useless, and announced that he would rewrite it from scratch.[12] The established deceivers were dubious about Strangeways's announcement and assumed he would resubmit the existing plan with some modifications.[15] However, he duly submitted a rewritten operation that was met, in Harmer's words, with "astonishment".[10]


Strangeways's revised Fortitude plan, and an operational implementation dubbed Quicksilver, invented an entire new field army but crucially without significant fictional forces. The skeleton of this new force already existed in the form of the First United States Army Group (FUSAG), commanded by Omar Bradley. It had been formed for administrative purposes but never used, however, the Germans had discovered its existence through radio intercepts. Strangeways proposed activating the unit, with a series of fictional and real formations.[15] The order of battle for the army would be intended to represent the bulk of Allied forces in England and therefore the main Allied threat.[16] To add credence to the importance of FUSAG, Bradley was replaced by Lt. Gen. George Patton, whom the Germans held in high regard and who was known to be a competitor to Montgomery.[17]

The Fortitude South story would be that FUSAG was being prepared to invade Pas de Calais some weeks after an initial diversionary invasion. This would then allow Operation Neptune's landings to be passed off as a distraction from the main invasion at a later date.[18] Pas de Calais offered a number of advantages over the real invasion site, such as the shortest crossing of the English Channel and the quickest route into Germany. As a result, Rommel had taken steps to fortify that area of coastline heavily. Strangeway's felt that this would help the deception seem realistic in the minds of German high command.[1]

A deception of such a size required significant organisation and input from many organisations, including MI5, MI6, SHAEF via Ops B, and the armed services. Information from the various deception agencies was organised by and channelled through the London Controlling Section. To help keep the approach well-organised Strangeways divided the implementation stages into six sub-plans code-named Quicksilver.[16][18]

Quicksilver Sub-Plans
Plan Special Means Description
Quicksilver I Leaks The basic 'story' of Fortitude South was to be leaked, under Quicksilver I, largely through the double agent network and some diplomatic channels.[19]
Quicksilver II Wireless traffic Radio deception was used to simulate the movement of troops across the south of England, with German listening posts expected to pick up the traffic.[20]
Quicksilver III Physical deception A display of dummy landing craft, including associated simulated wireless traffic, road signs and restricted areas.[21]
Quicksilver IV Physical preparations Any invasion target would have been prepared with attacks in advance of landings, so Quicksilver IV covered a number of air activities including bombing of the Pas-de-Calais beach area and tactical railway bombing immediately before D-Day.[22]
Quicksilver V Physical Deception Overall increased activity around Dover (for example giving impression of extra tunnelling and additional wireless stations) to suggest embarkation preparations.[23]
Quicksilver VI Physical Deception Night lighting deception to simulate activity at night where dummy landing craft were situated.
Dummy landing craft, used during Fortitude, at an unknown location in South-East England

The FUSAG deception was not primarily implemented with dummy tanks, airplanes, or other vehicles. At that stage of the war the Germans were unable to fly reconnaissance planes over England and therefore Strangeways felt that such effort would have been wasted.[note 3][14] However, temporary buildings were constructed and dummy landing craft were stationed at likely embarkation point in eastern and southeastern England.[24][25] As the FUSAG commander, Patton paid many of them a visit, along with a photographer, to ensure their location was noted.[26] The landing craft, built from wood and canvas and nicknamed Bigbob's, suffered from being too light. Wind and rain flipped many over or ran them to ground during the operation.[27]

Instead of extensive physical measures, the majority of Strangeway's plan relied on radio signals and leaks through double agents. Managing this information flow had to be done with caution – leaking supposed top-secret invasion plans would have been very obvious. Instead the deceivers used tactics developed by Clarke in Cairo. Agents were allowed to report minutiae such as insignia on soldiers' uniforms and unit markings on vehicles to allow the Germans to build up a picture. The observations in the south-central areas largely gave accurate information about the real invasion forces (Clarke had stressed that using as much real information as possible led to better outcomes). Reports from southwest England indicated few troop sightings, when in reality many units were housed there in preparation for D-Day. Reports from the southeast depicted largely notional Quicksilver forces. This approach aimed to convince German intelligence services of an order of battle for the Allied forces that placed the center of gravity of the invasion force opposite Pas de Calais.[28]

Fortitude North[edit]

Edinburgh Castle, the headquarters of the fictional British Fourth Army during Operation Fortitude

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 to delay reinforcement of France after the Normandy invasion. The plan involved simulating a buildup of forces in northern England and political contact with Sweden.[29]

During a similar operation in 1943, Operation Tindall, a fictional field army (British Fourth Army) had been created, headquartered in Edinburgh Castle.[30] It was decided to continue to use the same force during Fortitude. Unlike its southern counterpart, the deception relied primarily on fake radio traffic since it was judged unlikely that German reconnaissance planes could reach Scotland unintercepted.[29][31] 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, and the British media co-operated by broadcasting fake information, such as football scores or wedding announcements, to nonexistent troops.[31]: 464–466  Fortitude North was so successful that by late spring 1944, Hitler had positioned thirteen army divisions in Norway.[32]

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. That coincided with an increase in naval activity in the northern seas and in political pressure on neutral Sweden.[31]: 466–467 

Similar to the operation in the south, Fortitude North has a subsiduary plan used to implement the extensive radio deceptions. Code-named Operation Skye, the programme began on 22 March 1944, overseen by Colonel R. M. McLeod, and became fully operational by 6 April.[31] Skye was split into four sections, relating to different divisions of the Fourth Army[note 4]


On 20 July Ops (B) took over control of Fortitude South from R Force. Earlier the previous month, they had begun work to follow up the operation.[33] The new story centered 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 a second, smaller, Second American Army Group (SUSAG) would be formed to threaten the Pas de Calais.[34] The plan again met criticism from Strangeways. Firstly, he opposed the creation of so many fictional US formations in the face of a known manpower shortage. Secondly, the new plan reduced the threat to Pas de Calais which might give the German command confidence to move the Fifteenth Army to reinforce Normandy. As before, in late June, Strangeways rewrote the operation to ensure that the focus remained on Calais.[34] In his version, the Normandy beachhead was struggling to succeed and therefore Eisenhower had taken elements of FUSAG to reinforce its efforts. FUSAG would then be rebuilt with newly-arrived US formations with the aim of landing in France toward the end of July.[35]

Through this evolved plan, the Allies maintained the pretense of FUSAG and other forces threatening Pas-de-Calais for some considerable time after D-Day, possibly even as late as September 1944. That was vital to the success of the Allied plan by forcing the Germans to keep most of their reserves bottled up in wait for an attack on Calais that never came. That allowed the Allies to maintain and to build upon their foothold in Normandy.[36] Having served its purpose, on 28 September 1944 it was agreed to end the Fortitude deception and move any remaining operational deceptions in the field to the overall charge of Ops (B).[36]


The Allies were able to judge how well Fortitude worked because of Ultra, the signals intelligence that was obtained by breaking German codes and ciphers. On June 1, a decrypted transmission by Hiroshi Ōshima, the Japanese ambassador, to his government that recounted a recent conversation with Hitler confirmed the effectiveness of Fortitude. When asked for Hitler's thoughts on the Allied battle plan, he had said, "I think that diversionary actions will take place in a number of places – against Norway, Denmark, the southern part of western France, and the French Mediterranean coast",[37] and he added that he expected the Allies would then attack in force across the Strait of Dover.[37]

The deception was also assisted by very high German assessments of Allied capabilities; in an appreciation of 8 May von Rundstedt said:[38]

Observed tonnage of landing shipping could be taken as sufficient for 12 or 13 divisions (less heavy equipment and rear elements) for fairly short sea routes. In all (estimating the capacity of the other English ports not so far covered by visual and photo recce) probable employment of at least 20 and probably more divisions in first wave must be expected. To these must be added strong air-landing forces.

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 "diplomatic leaks" resulted in their discontinuance. Most deception in the south was carried out by means of false wireless traffic and through German double agents. However, these methods had significantly less impact for Fortitude North. In his 2000 book, Fortitude: The D-Day Deception Campaign, Roger Fleetwood-Hesketh, a member of Ops (B), concluded that "no evidence has so far been found to show that wireless deception or visual misdirection made any contribution". It is thought that the Germans were not actually monitoring the radio traffic that was being simulated.[39]

Overall, Fortitude was successful for several reasons:

  • The long term view 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. That is one of the early uses of a closed-loop deception system. The messages were usually encrypted by Fish, rather than Enigma machines.
  • Reginald Victor Jones, the Assistant Director Intelligence (Science) at the British Air Ministry, insisted that for reasons of tactical deception, 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 among the various elements.
  • General George Patton was the leader whom the Germans feared the most and whom they considered the Allies' best general.[40] Therefore, the German High Command believed that he would lead the daring attack.

Fictional depictions[edit]

Operation Fortitude was classified, along with all of the wartime deceptions, and initial accounts did not emerge until the 1970s. Once published, however, the story inspired a number of fictional accounts:

  • Eye of the Needle is a 1978 novel by Ken Follett about a Nazi spy stationed in the south of England who discovers the Allied deception and races to inform the German leadership. It was subsequently adapted into a 1981 film of the same name, starring Donald Sutherland.
  • Fall from Grace is a 1986 novel by Larry Collins about a French agent, Catherine Pradier, who risks her life to deceive the Nazis as to where and when the Allies will invade the Continent of Europe and begin the end of World War II.
  • Jack Higgins's 1991 novel The Eagle Has Flown ends with a conference between Adolf Hitler and two-high ranking German military intelligence officers, including Abwehr head Wilhelm Canaris, who are solidly convinced that the Allies are planning to invade Normandy, but Hitler is unswayed from his belief that Calais is the intended target.
  • The Unlikely Spy is a 1996 novel by Daniel Silva that likewise focuses on Allied attempts to carry out Fortitude as well as a German agent's race to discover the true plans.
  • Goodnight Sweetheart is a BBC TV comedy series that features a time-traveller, Gary Sparrow. In two episodes of Series 5 aired in 1998, Gary, when he returns to 1944, appears to be the double of one of General Charles de Gaulle's aides. He is used in that guise by MI5 and is sent to Calais; he makes contact with the French Resistance but is captured by the Gestapo. All of that was planned to reinforce the Pas-de-Calais invasion deception. Luckily, Gary is able to escape and to return to England.
  • Blackout and All Clear, is a 2010 two-volume novel by Connie Willis, about time-travelling historians who study the events of the Battle of Britain. One of the historians, posing as an American journalist, ends up working for Operation Fortitude.
  • Overlord, Underhand is a 2013 novel by American author Robert P. Wells, a fictionalized retelling of the Juan Pujol (Agent Garbo) double-agent story from the Spanish Civil War through 1944 that examines his role in MI5's Double-Cross System in selling Fortitude to the German High Command. ISBN 978-1-63068-019-0


  1. ^ The London Controlling Section retained central responsibility the use of diplomatic channels and double agents.
  2. ^ SHAEF was offered a list of names to choose from; Bulldog, Axehead, Swordhilt, Fortitude and Ignite
  3. ^ It has been suggested that the Army later encouraged the idea that the dummies were used to draw attention away from some of the other means of deception, such as double agents.
  4. ^ Operation Skye: (I) Fourth Army headquarters, (II) British II Corps, (III) American XV Corps (a genuine formation, but with fictional units added to its order of battle), (IV) British VII Corps.



  1. ^ a b Latimer 2001, pp. 218–232
  2. ^ a b Jablonsky 1991
  3. ^ a b Brown 1975, pp. 1–10
  4. ^ a b c d Levine (2011), p. 202
  5. ^ Holt (2004), p. 531
  6. ^ a b c d Levine (2011), pp. 203–204
  7. ^ a b Holt (2004), p. 532
  8. ^ a b Holt (2004), p. 533
  9. ^ Holt (2004), p. 534
  10. ^ a b Levine (2011), p. 208
  11. ^ Holt (2004), pp. 50–51
  12. ^ a b c Levine (2011), pp. 205–206
  13. ^ Holt (2004), p. 535
  14. ^ a b Holt (2004), pp. 536–537
  15. ^ a b c Levine (2011), p. 206
  16. ^ a b Holt (2004), pp. 578–579
  17. ^ Holt (2004), p. 541
  18. ^ a b Levine (2011), p. 207
  19. ^ Deuve (2011), pp. 231–233
  20. ^ Deuve (2011), pp. 234–238
  21. ^ Deuve (2011), pp. 238–239
  22. ^ Deuve (2011), pp. 239–242
  23. ^ Deuve (2011), pp. 242
  24. ^ Holt (2004), p. 537
  25. ^ Howard (1990), p. 120
  26. ^ Gawne (2002), p.
  27. ^ Janeczko (2017), pp. 162–163
  28. ^ Masterman (1972), p. 223
  29. ^ a b Sexton 1983, p. 112
  30. ^ Holt 2004, p. 486
  31. ^ a b c d Cave Brown 1975
  32. ^ Ambrose 1994, p. 82
  33. ^ Holt (2004), p. 584
  34. ^ a b Holt (2004), p. 585
  35. ^ Holt (2004), p. 586
  36. ^ a b Holt (2004), p. 630
  37. ^ a b Holt 2004, pp. 565–566
  38. ^ Kenyon 2019, p. 170.
  39. ^ Hesketh, p. 167
  40. ^ Beevor (2012), p. 571