Any electrical spark creates radio waves and acts as a transmitter. You hear sparks on a radio as interference. That's why lighting makes radios crackle, and even the tiny spark in a switch is enough to make a noise on the radio when turning on a light.
Illustrated with archival film and photographs, as well as interviews with those involved, the documentary traces the evolution of civilian involvement in radio-based intelligence during both world wars.
It was the tireless work of amateur radio enthusiasts during World War I, that initially convinced the Admiralty to establish a radio intercept station at Hunstanton. Playing an integral role during the war, technological advances meant that radio operators could pinpoint signals, thus uncovering the movement of German boats, leading to the decisive Battle of Jutland in 1916.
Wireless espionage was to play an even more important role during World War II, with the Secret Intelligence Service setting up the Radio Security Service, which was staffed by Voluntary Interceptors, a band of amateur radio enthusiasts scattered across Britain. The information they collected was interpreted by some of the brightest minds in the country, who also had a large hand in deceiving German forces by feeding false intelligence.