Over three episodes, Sir David reveals the legendary characters, audacious missions and makeshift intelligence gathering techniques, and recounts spy stories of true valour and ingenuity from the early 20th century to the modern day.
The series opens with the story of M, the legendary spymaster who singlehandedly created the British Secret Service, turning it from a bunch of civilian amateurs into a network of top agents who helped win World War I.
Sir David goes on to examine some of the lesser-known aspects of World War II. These are the stories of fearless heroism and intrepid reconnaissance in a world of cold-blooded assassins, sly saboteurs, elite commandos, playboy spies, double agents, super-villains and femmes fatales.
Finally, he searches out Britain’s eccentric amateur inventors and problem-solving masterminds, who played a pivotal role in the defeat of Hitler and created the mechanisms leading to hi-tech 21st century surveillance.