Winston Churchill was reported to have told King George VI, when presenting to him Stewart Menzies (head of the Secret Intelligence Service and the person who controlled distribution of Ultra decrypts to the government): "It is thanks to the secret weapon of General Menzies, put into use on all the fronts, that we won the war!" F. W. Winterbotham quoted the western Supreme Allied Commander, Dwight D. Eisenhower, at war's end describing Ultra as having been "decisive" to Allied victory. Sir Harry Hinsley, Bletchley Park veteran and official historian of British Intelligence in World War II, made a similar assessment about Ultra, saying that it shortened the war "by not less than two years and probably by four years"; and that, in the absence of Ultra, it is uncertain how the war would have ended.
The RAF Intelligence Branch dates back to 1939 following the outbreak of the Second World War, however personnel were employed in intelligence duties in the RAF since its formation in 1918.
The Special Operations Executive (SOE) was a World War II organisation formed to conduct espionage, sabotage and reconnaissance in occupied Europe (and later, also in occupied Southeast Asia) against the Axis powers, and to aid local resistance movements. The SOE was operational from July 1940 to January 1946.