‘PO Box 500, London W2’ – the nondescript address from behind which one of the world’s most famous secret services hid: MI5. Drawing on previously secret sources, this book lifts the lid on Britain’s Security Service in its battle against German and Soviet espionage. It tells the sensational stories of the officers and agents and the enemies they confronted, from MI5’s creation in 1909 under the direction of Vernon Kell, Britain’s first spymaster.

Building on the service’s wartime success, Maxwell Knight (‘M’), MI5’s charismatic and eccentric agent runner, penetrated Soviet and Fascist spy networks during the 1920s and 1930s. His agent, ‘Miss X’, was instrumental in breaking the Percy Glading spy ring run by the Soviets, while the beautiful Joan Miller and ‘Miss Z’ helped bring to justice Tyler Kent, who was passing information to the Axis powers.

ABOUT THE AUTHORS

THOMAS HENNESSEY is Reader in History at Canterbury Christ Church University. He was an advisor to the award-winning BBC TV documentary Endgame in Ireland. He is a Fellow of the Royal Historical Society. He lives in London & Canterbury.

CLAIRE THOMAS is a historian who specialises in the early years of the Cold War. She is currently working on a history of Britain’s involvement in the Korean War. She lives in Folkestone.