Angels Eight

Preparation for OVERLORD -- invasion of Europe

The British Army together with remnants of French and Belgian forces evacuated the beaches of Dunkirk in the summer of 1940. They left all their equipment behind and they slunk home as a defeated army, but the soldiers together with every British and Commonwealth citizen around the world knew that one day they would have to return -- to invade France and defeat Hitler.

The United States joined the war against Germany and Japan in December 1941 and within months argued for an invasion of Europe, however it was clearly out of the question at that time. The Battle of the Atlantic was running in Germany’s favour, threatening the flow of essential war materials to Britain -- this battle had to be won first. Only after establishing safe seaways could the US and Britain amass the necessary military supplies in England. A not so obvious second requirement before an invasion of Europe could be accomplished, was the taking and assembling of massive amounts of photographic intelligence of enemy defences and of the topography. And there was an even more obvious requirement -- the numbers of available assault landing craft to accomplish the crossing were not nearly enough to handle five divisions. As late as the fall of 1943 this was still the case.

Germany invaded the Soviet Union in the summer of 1941, halted in winter and resumed in spring 1942. After a year of ferocious fighting the initiative passed to the Russians after Stalingrad in February 1943. The British and Americans sent massive military aid to the Soviet Union to fuel this reversal, but the Soviet effort was achieved at an enormous cost in lives and Stalin insisted the Allies invade Europe as soon as possible to further relieve the pressure on his forces. At a summit conference in Teheran on 28 November 1943, President Franklin Roosevelt of the USA and Prime Minister Winston Churchill of the UK met Marshal Joseph Stalin of the Soviet Union for the first time. The Western Allies told Stalin they would invade Europe in May 1944. An official communiqué released after the meeting referred to, "complete agreement as to the scope and timing of operations which will be undertaken from the east, west and south."¹ Stalin was also told that General Dwight Eisenhower would be appointed Supreme Commander of the invasion forces.

The Allied leaders knew that smashing through Hitler’s Atlantic Wall defences, landing in Europe, resisting counter-attack and breaking out of the beachhead would be an ‘all-or- nothing’ affair. If the assault was beaten at the beaches – as both Adolph Hitler and his generals insisted it must – the Allies would have to wait a year or more to try it again for the invasion would directly involve some two million people – a million landed as military forces and another million dealt with people, materials and logistics in the United Kingdom. Apart from the horrendous loss of lives and materiel should the invading forces be thrown back into the sea, the blow to morale would cripple efforts to re-group.

Preparation for the invasion of Normandy required not only the usual assemblage of men and materials to give it any chance of success, but it required many other ingredients in order to guarantee that success. Surprise – a most unlikely element to achieve – would have to be striven for; every effort had to be made to mislead the Germans as to time and place. Air supremacy over the landings and over the lodgment was an absolute necessity; enemy aircraft must not be allowed to attack the crowded beaches or hamper ground operations. Intelligence from the interception of communications, French Underground and saturation photography of the target areas were another essential. Naval control of the Channel crossing lanes was another essential; enemy surface vessels or U-boats could cause a disaster if they broke through the ring of defenders.

In all the accounts written by the key players immediately after the war – Churchill, Eisenhower, Montgomery, and others -- no reference was made to breaking the German military communication code. Thirty years passed before the first leak occurred regarding one of the most astounding accomplishments of the entire war. The world learned that as early as 1939 the Polish and the British had secretly seized a German encoding machine called ENIGMA. With the machine in hand they broke the German code and when hostilities were hot in 1940, British code-breakers were able to regularly interpret German military messages. The German Army used its ENIGMA machines to direct troop movements and for all forms of military communiqués and the navy used it to communicate with U-boats. The Germans were convinced that the code could not be broken.

A message was broken into four-letter segments and entered into the ENIGMA machine. The machine had a series of wheels whose coordinated positioning provided various combinations to scramble the letters. Without prior knowledge of the combination of wheels, there were thousands of billions of solutions – impossible to de-code. However, it is now known that the German operators took short cuts, including in the message a master setting necessary for de-coding, rather than having the master setting transmitted in some other way. In so doing, the number of possible solutions to the unscrambling of a message was reduced to a point where the British electro-mechanical computers could decode it.

The decoding endeavour was called Operation ULTRA, and the activity was centred at Bletchley Park in Buckinghamshire. By war’s end 10,000 people were employed there. They picked up radio signals from all over the world, de-coded them, translated them and passed them to the highest Allied leadership. In Churchill’s memoirs he refers to information he received daily from a ‘secret source’. Only in recent years has it become known what that source was, for only in 1994 were decodes of Churchill’s ULTRA messages de-classified and made public.

This marvellous scoop by the intelligence community provided the planners of the invasion of Europe with the disposition of German forces literally as they occurred. At the end of May 1944 for instance, the Allies received a fairly precise location for most of the 28 German divisions between Amsterdam and Brest, and a very accurate account of where the armour was located. This last came in an intercepted message announcing that the Inspector-General of Armour would inspect all units in Western Europe, and the message went on to give his itinerary, with the number of days to be spent at each location.