Operation Fortitude

Operation Fortitude was the codename for the deception operations used by the Allied forces during World War II in connection with the Normandy landings. It was divided into Fortitude North, a threat to invade Norway, and Fortitude South, designed to induce the Germans to believe that the main invasion of France would occur in the Pas de Calais rather than Normandy. Fortitude South was one of the most successful deception operations of the war, and arguably the most important.

Both Fortitude North and Fortitude South were related to a wider deception plan called Operation Bodyguard.

Fortitude North

Fortitude North consisted of the creation of the fictional British Fourth Army, complete with subsidiary units and headquarters. Fake radio traffic was created (an operation called Operation Skye), along with media reports of units' activities.

British diplomats also began negotiations with neutral Sweden in order to obtain concessions that would be useful in the event of an invasion of Norway, such as the right to fly reconnaissance missions over Sweden and the right to refuel planes that made emergency landings. These negotiations were made not in the hope of obtaining the concessions but with the intention that news of the negotiations would reach the ears of the Germans.

Order of Battle - British Fourth Army fictional - HQ Edinburgh

British II Corps (fictional - HQ Dundee)
- 55th Division (fictional)
- 3rd Division
- 58th Division (fictional)
- British 113th Independent Infantry Brigade (garrison for Orkney and Shetland Islands)

British VII Corps (fictional - HQ Stirling)
- 52nd Division
- U.S. 55th Division (fictional)
- U.S. Ranger battalions

United States XV Corps stationed in Northern Ireland

A careful mix of genuine and artificial units was maintained. Fourth Army was supposedly created from the Northern District, an administrative formation controlling units stationed or training in Scotland.

Fortitude South

Fortitude South was conducted with the intention of convincing the Germans that an invasion would come to the Pas de Calais - a logical strategic choice for an invasion since it was the closest part of France to England. While it was hoped that this would reduce the number of troops in the Normandy area at the time of the invasion, even more important was to dissuade the Germans from reinforcing the Normandy battleground in the days immediately after the invasion. To this end the Allies hoped to convince the Germans that the Normandy invasion, when it occurred, was a diversion, and the main invasion was still to come near Calais.

Operation Quicksilver

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. By placing FUSAG in the south-east, German intelligence would (and did) deduce that the center of gravity of the invasion force was opposite Calais, the point on the French coast closest to England and therefore a likely landing point.

In order to facilitate this deception additional buildings were constructed; dummy vehicles and landing craft were placed around possible embarkation points. A huge amount of false radio traffic was transmitted, commensurate with a force of that size.

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 channeled through the London Controlling Section under the direction of Lieutenant-Colonel John Bevan.

Double Agents

The Germans had about 50 agents in England at the time, but B1A (the Counter-Intelligence Division of MI5) had caught and recruited many of them as double agents. In fact, although they did not know it, MI5 controlled all of the German agents in Britain at the time. They planned to feed German Intelligence a misleading picture of the invasion preparations via their own agents. Reports were sent indicating troop movements in the south-east, opposite the Pas de Calais. However no troop movements were reported in the west of England, the natural jumping-off point for a Normandy invasion. Additionally infrastructure was reported as being incomplete, and troops as untrained or ineffective, to give the picture that an invasion was scheduled for later in the year.

The two key double agents for Fortitude were:

GARBO: Juan Pujol - even awarded the Iron Cross by German leader Adolf Hitler himself
BRUTUS: Roman Garby-Czerniawski

The Allies were able to easily judge the effectiveness of these strategies. ULTRA intelligence — that gained from the breaking of German codes and ciphers, such as the Enigma machine — was able to provide an indication of the German high command's responses to their actions. They 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. 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 which never came, thereby allowing the Allies to maintain and build upon their marginal foothold in Normandy.

Myths

Fortitude South has become hedged about with a number of myths and errors. To correct the most important of these:

Fortitude was not devised or developed either by the London Controlling Section, the key deception planning element for the British Chiefs of Staff, or by the "Twenty (XX) Committee". Fortitude North was devised, and its conduct supervised, by a section of Eisenhower's SHAEF operations staff known as "Ops (B)." Fortitude South was devised, and its conduct supervised, by Colonel David Strangeways, the chief deception officer for General Montgomery's 21st Army Group, which was to carry out the actual invasion of Normandy.
Fortitude South was put over almost entirely by means of misinformation furnished to German intelligence through double agents controlled by the British, together with deceptive radio signaling depicting the concentration of forces in southeastern England. The use of dummy tanks and planes was limited, since the German capability for aerial reconnaissance of England was small. Some dummy tanks and landing craft were positioned around coastal ports.
Fortitude South did not involve the use of fake divisions and other units to any extent. Rather, it was built primarily around misleading the Germans as to the location of real units. (A follow-up plan of limited duration, Fortitude South II, did involve fake units.)
The significance of the German countermanding of the movement of one armored division after D-Day as the result of a message from a double agent was not particularly great and the importance of this event has been wildly overblown.

Reasons for success

Some of the key reasons why this operation was so successful:

The long term view taken by British Intelligence to cultivate these agents as channels of misinformation to the enemy.
The use of ULTRA decrypts to read ENIGMA coded messages between Abwehr and German High Command which quickly told them the effectiveness of the deception tactics. This is one of the early uses of a closed-loop deception system.
The extensive nature of the German Intelligence machinery, and the rivalry amongst the various elements

Quotes

"So how successful was (Operation) Fortitude? It couldn't have been more successful" — Stephen Ambrose

References

Howard, Sir Michael, Strategic Deception (British Intelligence in the Second World War, Volume 5) (Cambridge University Press, New York, 1990)
Holt, Thaddeus, The Deceivers: Allied Military Deception in the Second World War (Scribner, New York, 2004)
Harris, Tomas, "GARBO, The Spy Who Saved D-Day", Richmond, Surrey, England: Public Record Office, 2000, ISBN 1873162812
Hesketh, Roger, "Fortitude", Overlook Press, New York, 2000, ISBN 1585670758
Masters thesis of Whitney talley Bendeck

World War II deception operations | Operation Overlord

Gourt Home::Gourt :: Operation Fortitude