John le Carré’s spy secrets including ‘very bad things’ could now be published

His gripping tales of intrigue and espionage made him a best-selling author.

But John le Carré’s most explosive book may not yet be published – revealing his greatest secrets.

The thriller writer who died on Saturday aged 89, began his career as a spy in post-war Europe.

He wrote his first novel, Call For the Dead published in 1961, while working undercover for MI6 at the British embassy in Bonn, where he recruited and ran secret agents and conducted interrogations at the height of Cold War tensions.

But while his novels appeared to allude to real life events, the author remained tight-lipped about what he knew about the British spy operations he had been part of.

The reclusive writer only confirmed he was “for a time engaged in that work” and said later: “We did very bad things.”

He did authorise a biographer to reveal secrets about his life, allowing him access to private papers on Britain’s Cold War activity, but the agreement came with a significant clause.

Author Robert Harris said that after he approached Le Carré, real name David Cornwell, in the 1990s “he agreed to help if I agreed not to publish until after his death”.

Harris added: “David has got a great story to tell. Will people find it shocking? Some will.”

Revelations might include details about the scandal that ended Le Carré’s secret service career – his MI6 colleague Kim Philby being exposed in 1963 as a Soviet double-agent.

Le Carré served in MI5 and MI6 during a turbulent time for British intelligence, when a number of spies were exposed as Communist traitors.

Most of what happened during that time has not been told – and Le Carré wanted to keep it that way during his lifetime.

Once, after declining a request to be interviewed about his intelligence work, he said: “It’s a matter of pride to me that nobody who knows the reality has so far accused me of revealing it.”

He also went to great lengths to suppress attempts to publish details about his personal life.

When one writer, Graham Lord, approached publishers with a proposal for a biography, including salacious details about Le Carré’s mistresses as well as his secret service work, Le Carré’s lawyers bombarded him with threatening letters.

Lord said: “It was probably the worst time of my life.”

Le Carré did eventually permit fans to know a little more about him when he collaborated with a biography by Adam Sisman in 2015.

It revealed a life as intriguing as any of his fictional characters.

He was born in Poole, Dorset, in 1931.

His mum left five years later, and he did not meet her again until he was 21.

He was thrust into a secretive world at an early age because his dad was a conman who had been in jail.

Helping his father dodge the authorities and bailiffs taught Le Carré the art of subterfuge.

He said: “I became a little spy. You either spied on him or for him.”

Le Carré joined the Intelligence Corps of the Army in 1950.

Based in Austria, he worked with agents crossing the Iron Curtain into Eastern Europe.

After returning two years later to study at Oxford, he worked with MI5 to try to identify Soviet spies.

He wed in 1954 and had three sons. In 1960 he was transferred to MI6 and was sent to Germany, posing as a diplomat.

He wrote under a pen name as intelligence service rules meant he could not use his real name.

Le Carré insisted his novels were all made up, saying: “I’m a liar. Born to lying, bred to it, trained to it by an industry that lies for a living.”

After leaving the Foreign Office, he got divorced, re-married and had another son – author Nick Harkaway.

Le Carré moved near to Land’s End in Cornwall where he remained an enigma.

“A good writer is an expert on nothing except himself,” he once said. “And on that subject, if he is wise, he holds his tongue.”