A historian’s new book examines the valiant spying effort made at a highly secretive house in Buckinghamshire, which may have saved London from the same fate as Hiroshima.

 Dr Helen Fry has written Spymaster: The Secret Life of Kendrick, which tells the story of the top MI6 officer at the heart of Britain’s Second World War intelligence work, Colonel Thomas Kendrick.

Kendrick at his desk in Latimer House in the Second World War

From 1942, he worked for the British Secret Service from Latimer House near Chesham where he led the operation of spying on German prisoners of war and eavesdropping their conversations.

Dr Fry said: “I find the topic fascinating, I wanted to find out more and more and uncover it in the book. Kendrick has not had much attention and he has taken a lot to his grave, I wanted to record it.”

Intelligence officers would describe the house as ‘a very secret place’. Secrecy was woven into the fabric of their lives, they signed an official secrets act and they were not allowed to tell anyone where they were.

Former Prime Minister, Winston Churchill would frequently travel the 30 miles from London to visit the house.

Latimer House was one of three secret intelligence sites that was run by Kendrick, across them all, 10,000 prisoners’ conversations were bugged. One of the highest ranking prisoners out of the 10,000 who passed through Latimer House was Hitler’s deputy leader in the Nazi Party, Rudolf Hess.

“I think that they chose Latimer House for the headquarters as it is close to London so easy for intelligence officers to come and go but it is isolated. The whole place is riddled with secrets,” the historian said.

In 1943, secret listeners at Latimer House overheard prisoners discussing Hitler’s secret powerful missiles, the V1 and V2.

As a result of these conversations, Churchill gave the order for a special mission to bomb the missile development sites.

Dr Fry said: “Without this discovery, we would have lost the war because Hitler planned to fire 300 of these a day on London alone.”

Fritz Lustig, who is of Jewish origin and was originally from Berlin, was one of the secret listeners who eavesdropped on the German prisoners.

He was there from 1943 to 1946 and he would monitor the prisoners and what they said in the M Room.

The 95-year-old German refugee said: “Every important discussion by the prisoners was recorded. We did not realise how important our jobs were at the time, we were very pleased that we could help with the war effort. There was always something to record.”

Microphones were bugged in places such as light fittings and plant plots listening to any information that the prisoners passed onto each other and withheld from the officers.