Radar and the Secret Wireless War (Their Finest Hour)

Until 1940, British and German intelligence were operating at the same levels. Both had both success and minor errors or had fallen foul to believing the 'bluff' of the other, but neither had truly developed an advantage. In Britain however, the recruitment of amateur radio enthusiasts was part of a developing, elaborate plan to take intelligence to a tactical offensive level by sending false information to German field officers. This, coupled with the development of a defensive strategy using radio listening devices capable of reporting enemy aircraft movements, moved Britain into a new phase and form of warfare, which has been used ever since.