Allied code name for the deception campaign designed to conceal the true objective of Operation OVERLORD, the invasion of France on D-Day, 6 June 1944. Certainly the most comprehensive and sophisticated undertaking of its kind ever attempted, the operation consisted of FORTITUDE NORTH, intended to imply an imminent threat to Norway, thereby tying up valuable Axis troops there, and FORTITUDE SOUTH, which conveyed the impression that the Allies intended to land in the Pas-de-Calais a couple of weeks after a diversionary feint in Normandy.
Conceived by Roger Hesketh and executed by Supreme Headquarters Allied Expeditionary Force’s deception staff, FORTITUDE passed information about a nonexistent First U.S. Army Group, commanded by Gen. George Patton, assembling in East Anglia in anticipation of an invasion to be launched from Dover. The real forces, concentrated in the west of England, were heavily camouflaged, while Luftwaffe aerial reconnaissance flights were allowed to photograph what appeared to be huge numbers of aircraft, tanks, and landing craft in East Anglia—all of whichwere rubber and plywood dummies. Bogus wireless traffic was generated to support the deception, and supposedly indiscreet newspaper stories were published indicating the presence of foreign troops in the southeast. In addition, MI5’s double agents inundated the enemy with reports of men and armor moving toward the Channel ports, with the final touch being given by GARBO, who transmitted a message on the eve of the assault warning that an imminent, minor attack on Normandy would be followed a fortnight later by a massive offensive across the shortest stretch of the English Channel.
Enemy documents recovered after the war proved that the Germans had accepted a greatly exaggerated Allied order of battle, including the First Army Group, and had readily believed that the Pasde-Calais had been D-Day’s true objective, to the point that the First SS Panzer Division had been prevented from counterattacking in Normandy and was ordered back to the Franco-Belgian border on D+3.