(Since May 1941 and the capture of Germany’s Enigma coding machine from a German U-boat, British codebreakers, primarily based in Bletchley Park in Buckinghamshire, had been able to decode and read German communications. In the lead-up to D-Day and during the subsequent Battle of Normandy, the intelligence gleaned from Enigma provided vital information to the Allies regarding German movements and plans, often resulting in modifications to their own plans and allowing Allied troops to be on the ready.)
The Allies knew that preparing an armada consisting of vast numbers of men, vehicles and equipment could hardly go undetected by German intelligence, the Abwehr. Thus, in a massive operation codenamed Bodyguard, great efforts were made to deceive the enemy into believing that any landings in Normandy were a mere feint while the real invasion would take place elsewhere. The principal elements of Bodyguard were Operations Fortitude North and Fortitude South. The objective of Fortitude South was to mislead the Germans into thinking that the main thrust of an Allied attack would arrive at Calais. The greater the proportion of the Germany army the Allies could keep away from Normandy, the more time to land successive waves of men and the increased chance of securing a firm foothold on the continent before the Germans rushed in the bulk of their troops.
An inflatable tank.
The Allies established a fake army, the First United States Army Group (FUSAG), based near Dover, opposite Calais, commanded by one of the USA’s most famous generals, George Patton, Jr. There were dummy tanks and gliders to fool German air reconnaissance, fake radio messages, fake military camps and headquarters, and dummy oil tanks. The commanders even trained a soldier-cum-actor, M. E. Clifton James, to impersonate Montgomery and sent him out to Gibraltar and North Africa. (Clifton James, who had lost a finger during the First World War, had to have a prosthetic one made, and, for the duration of the operation, was obliged to stop smoking and drinking – Montgomery did neither.)
Agents were used to feed false information to the Germans; the most valuable being a Spaniard, Juan Pujol Garcia, a double agent codenamed ‘Garbo’, after Greta, in Britain and ‘Arabel’ in Germany. In the six months leading up to D-Day, Garbo sent the Germans over 500 messages, many of them containing correct information to help maintain his ‘reliability’. The Germans trusted him as a ‘well-regarded source’, never realizing where his true loyalty lay. Garbo helped reinforce the idea that the main thrust of an Allied invasion would be directed at Calais or possibly Norway, and would probably take place sometime in July 1944. Indeed, to prove to the Germans the extent of Arabel’s loyalty, on 6 June, Garbo even sent the Germans an urgent message warning them that Operation Overlord had just been launched, but timed so that the Germans had insufficient notice to react with any real effectiveness. Thus, the Germans’ trust in their Arabel was complete, and they utterly believed him when he messaged again to warn them that the assault on Normandy was only a diversionary attack to distract German attention from the main thrust due in Calais. Thus, as the first waves of troops headed for the Normandy beaches, the German command held their tanks back in readiness near Calais. Had this vital ruse failed, and had the Allied soldiers met the full force of the panzer divisions, the result might well have been very different.
Meanwhile, Fortitude North aimed to deceive the Germans that a joint Anglo-Soviet invasion would land at Trondheim on the coast of Norway. Another fake army was established, the British Fourth Army, based in Edinburgh, and false information fed to the Germans by two Norwegian double agents, codenamed Mutt and Jeff (although the British later had their doubts about ‘Mutt’ and subsequently interned him). Indeed, at the launch of Overlord, some 400,000 German troops were, in the event, needlessly stationed at the ready on the coast of Norway. Other plans aimed at deceiving the Germans included false attacks via Spain, the west coast of France, the west coast of Italy, plus Albania, Greece, Romania and Sweden. The deception worked: far fewer Germans were stationed at the beaches because Hitler had them posted across north-west Europe, while German troops bet each other on where the invasion would land.
Operation Fortitude’s second objective, following D-Day, was to persuade the Germans that the invasion of Normandy was but a feint, and that the main Allied landings were still to come in the Pas-de-Calais. By the time the Germans fully realized that they had been deceived, it would be too late.
In late June 1943, COSSAC’s draft plans for the invasion were presented to a conference held in Scotland, chaired by Mountbatten. Having received Mountbatten’s approval, and confirmation that Normandy was indeed the preferred point of invasion, the plans were then presented to Churchill and Roosevelt, and the Canadian prime minister, William Mackenzie King, at the Quadrant Conference held in Quebec that August. It was here that the Allies prioritized the defeat of Germany over that of Japan, and set the date of 1 May 1944 for ‘D-Day’. (The term ‘D-Day’ was a commonly used term during the war signalling the planned day of attack. The ‘D’ merely stood for Day. The hour of attack was similarly termed ‘H-Hour’, the ‘H’ standing for Hour.)
Italy
It was also at the Quadrant Conference that the Allied leaders decided to invade mainland Italy within the month. Allied troops had landed on the island of Sicily the previous month, on 10 July, where they had enjoyed an ecstatic welcome from the islanders. On 25 July, the Italian fascist dictator, Benito Mussolini, had been ousted from power and had since been held in captivity by the new Italian government. By mid-August, German forces had withdrawn from Sicily by crossing over the narrow Strait of Messina on to the Italian mainland. On 3 September, the Allies invaded. Five days later, Italy surrendered and swapped sides to join the Allies.
The first of the so-called ‘Big Three’ conferences, the big three being Churchill, Roosevelt and Stalin, was held in Tehran, 28 November to 1 December 1943. It was at Tehran that Stalin agreed, on the condition that the second front would be opened by May 1944, to launch a counteroffensive against Germany from the east, and, once Germany had been defeated, to join the Allied war against Japan.
Meanwhile, in Britain, preparations and intense training ahead of D-Day had begun in earnest.
Dwight D. Eisenhower and Air Chief Marshal Sir Arthur Tedder.
With three-quarters of the ground forces being American, it was inevitable that the overall commander of Operation Overlord was, likewise, going to be an American. Sure enough, in December 1943, the command structure for Operation Overlord was decided: the Supreme Commander was to be a Texan, General Dwight D. Eisenhower, with a Scotsman, Air Chief