Wartime consequences

Wartime consequences

F.W. Winterbotham summarizes the wartime consequences in the last chapter of his book.[8]

During the Battle of France (May–June 1940), the Allies, especially the French, failed to take proper advantage of Ultra, though Ultra intelligence helped organize the evacuation of the British Expeditionary Force (BEF) from Dunkirk.

In the summer of 1940, British cryptanalysts, who were successfully breaking German Air Force Enigma-cypher variants, were able to give Churchill information about the issuing of maps of England and Ireland to the Sealion invasion forces. Ultra also revealed to the British that the threat of invasion was over, when on September 17 Hitler authorized the dismantling of aircraft loading ramps at Dutch airfields.

During the Battle of Britain, Ultra intelligence was used by Air Chief Marshal Sir Hugh Dowding to optimally deploy the limited RAF Fighter Command assets.

Breaking of some messages (not in German Enigma) led to the defeat of the Italian Navy at Cape Matapan (March 27–29, 1941), preceded by another "fortuitous" search-plane sighting. British Admiral Cunningham also did some fancy footwork at a hotel in Egypt to prevent Axis agents from taking note of his movements and deducing that a major operation was planned.

Ultra intelligence was of considerable assistance to the British (Montgomery being "in the know" about Ultra) at El Alamein in Western Egypt in the long-running battle with the Afrika Korps under Rommel.

Intelligence from signals between Adolf Hitler and General Günther von Kluge was of considerable help during the campaign in France just after the Allied D-Day landings, particularly in regard to estimates of when German reserves might be committed to battle.

On the other hand, the Red Army was aware of the German buildup, dispositions and precise time of attack prior to the Battle of Kursk, even without the Ultra information provided to them.[citation needed] However, some evidence suggests that the Lucy spy ring in Switzerland, which provided crucial information about Stalingrad and Kursk, was actually a conduit for passing Ultra information to Moscow without detection by the Germans.