Operation Fortitude was a military deception operation by the Allied nations as part of Operation Bodyguard, an overall deception strategy during the buildup to the 1944 Normandy landings. Fortitude was divided into two subplans, North and South, and had the aim of misleading the German High Command as to the location of the invasion.
Fortitude had evolved from plans submitted by Noel Wild, the head of Ops (B), and John Bevan, from the London Controlling Section in late 1943. Early revisions in January 1944 suggested a fictional buildup of troops in southern England with the hope of drawing German attention to Pas-de-Calais. Colonel David Strangeways, head of Bernard Montgomery's R Force deception staff, was unimpressed with the approach. He was widely critical of the original plan and eventually rewrote 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 southern 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 had been purely a diversionary attack.
Background
Fortitude was one of the major elements of Operation Bodyguard, the overall Allied deception stratagem for the Normandy landings. Bodyguard's main objectives were to ensure that the Germans would not increase troop presence in Normandy and to do so by promoting the appearance that the Allies 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 the Oberkommando der Wehrmacht (German High Command) to believe in specific mainland invasion objectives.
The problem facing the Allies was that France was the most logical choice for an invasion into German-occupied 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 Army formations. That meant that any deception would have to convince the German high command that the Allies were not committing their full forces into Normandy, but holding many of those formations in reserve. After the landings, there would then need to be some way to delay the movement of German reserves to the Normandy beachhead to prevent a potentially disastrous counterattack.
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 focused on creating confusion about the Allied Channel crossing, and Fortitude North, staged out of Scotland, introduced a threat to occupied Norway. 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 D. 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.
Deception techniques
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 and used a number of methodologies which had come to be referred to as "special means." They 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 them were recruited as double agents under the Double Cross System. For Fortitude, 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. He 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.
Planning
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. That iteration aimed to take advantage of the likelihood that the Germans would notice invasion preparations in southern England. 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.
Colonel David Strangeways, head of Montgomery's R Force, raised concerns about the entire plan. 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 be forced to respond in defence. He was concerned the Germans might well be aware of the Allied readiness in southern England and so they would be alert to the risk of an invasion in early June. However, they would realise this gave them several weeks to defeat any bridgehead and return to defend Calais. On 25 January, Montgomery's Chief of Staff, Francis de Guingand, sent a letter to the deception planners that asked them to focus on Pas-de-Calais as the main assault and was almost certainly sent at the behest of Strangeways.
With those criticisms in hand, Wild produced his final draft for Fortitude. In the revised plan, which was 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. After the real invasion had landed, the story would change to suggest 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. At that point, Winston Churchill judged 'Mespot' to be an unsuitable name and so 'Fortitude' was adopted from an alternative list on 18 February.
Strangeways rewrite
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
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". 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 beginning of the war and had extensive experience of deception operations.
In the North African campaign, he had learned Clarke's maxim that deception relied on getting the enemy to do something, not just to think something, and so his criticism focused on that. He pointed out that convincing the Germans of so many fictional divisions would be difficult, and even more so would be convincing them of Montgomery's ability to manage two entire invasions at the same time. Wild's plan outlined ten divisions for the Calais assault, six of them being 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 as the main assault after D-Day. 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.
Strangeways's objections were 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. Finally, in a 23 February meeting between R Force and Ops (B), Strangeways tore up a copy of the plan, declared it useless, and announced that he would rewrite it from scratch. The established deceivers were dubious about Strangeways's announcement and assumed that he would resubmit the existing plan with some modifications. However, he duly submitted a rewritten operation that was met, in Harmer's words, with "astonishment".
Quicksilver
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 the 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, but the Germans had discovered its existence through radio intercepts. Strangeways proposed activating the unit, with a series of fictional and real formations. 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. To add credence to the importance of FUSAG, Bradley was replaced by Lieutenant General George Patton, whom the Germans held in high regard and who was known to be a competitor to Montgomery.
The Fortitude South story would be that FUSAG was being prepared to invade Pas-de-Calais some weeks after an initial diversionary invasion. That would allow Operation Neptune's landings to be passed off as a distraction from the later main invasion. Pas-de-Calais offered a number of advantages over the real invasion site, such as by being the shortest crossing of the English Channel and the quickest route into Germany. As a result, Erwin Rommel had taken steps to fortify that area of coastline heavily. Strangeways felt that would help the deception seem realistic in the minds of German high command.
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 subplans, codenamed Quicksilver.
The FUSAG deception was not implemented primarily with dummy tanks, aeroplanes, or other vehicles. At that stage of the war, the Germans were unable to fly reconnaissance planes over England and so Strangeways felt that such effort would have been wasted. However, temporary buildings were constructed and dummy landing craft were stationed at likely embarkation points in the East and the South-East of England. As the FUSAG commander, Patton paid many of them a visit, along with a photographer, to ensure that their location was noted. The landing craft, built from wood and canvas and nicknamed Bigbob's, suffered from being too light. Wind and rain flipped many of them over or ran them to ground during the operation.