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Western Europe 1939-1945: D-Day

Why was D-Day successful?

The role of the intelligence services

An example of Allied deception tactics on D-Day

Catalogue Ref: AIR 20/4349

Dummy aircraft; AIR 20/4349
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What is this source?

This is a British photograph of an aircraft on an airfield in England.


By 1943 British intelligence services had cracked a number of German codes. What was even more valuable was that the Germans were not aware of the extent to which their codes had been cracked.

What’s the background to this source?

By late 1942 the tide began to turn against Germany. From 1943 to 1944, British Empire and US forces began a build up of troops and equipment to drive the Germans out of the lands they had invaded in 1940. The landings took place in June 1944.


German naval forces and aircraft closely watched the Allies’ preparations. It was simply not possible to hide a force as large as the D-Day invasion force but the Allies did try very hard to keep the Germans guessing about exactly where the invasion would take place.

It’s worth knowing that...

The fact that the Germans did not know that the Allies knew what they were thinking was incredibly useful. Apart from any other advantages, it allowed the Allies to see whether their plans to deceive the Germans were working.


The aircraft in this photograph is a wooden fake. From the air it would have been almost impossible to spot. Large numbers of fake tanks and aircraft were placed in the east and south east of England to make the Germans think the invasion would come near Calais or Dieppe (the shortest crossing). Since the Germans thought this was going to happen anyway, these fakes probably convinced the Germans they were right, when in fact they were mistaken!

How does this source help us to understand why D-Day was successful?

  1. Study the photograph. Did you realise this aircraft was a wooden fake?
  2. Do you think it is possible that seeing large numbers of ‘aircraft’ and other equipment like this might have influenced German views of what was happening?
  3. How would you sum up the main value of this source to the historian?
  • Will you include this source in your storyboard?
  • If you do use it, what are the main points you will make in your caption?

Use this framework to plan your storyboard.