It was a chance conversation which changed the course of history and led to the unveiling of one of Britain’s greatest traitors. Now the key role a Jewish woman had in exposing the infamous double-agent, Kim Philby, has been dramatised for television.

A new drama A Spy Among Friends is based on the non-fiction novel by Ben Macintyre and opens with the whirr of a tape as a detective says: "We are in the home of Mrs Flora Solomon on January 8 1963.".

We then see actress Anastasia Hill, who plays Flora, tell the detective: "I very much regret it has taken all these years to realise who he is and the despicable things he has done."

The drama, which starts on new streaming channel ITVX on Thursday, focuses on the friendship between Philby, played by Guy Pearce, and Damian Lewis as his friend Nicholas Elliott, a fellow secret agent who was fooled and fooled again by the man who was spying for Russia while in a top position in the SIS (Secret Intelligence Service, the forerunner to MI6). But actually, the friendship between Philby and Solomon would be an even more fascinating tale.

Born Flora Benenson in Russia in 1895, the daughter of an oil tycoon, Flora had an affair as a young woman with Russian prime minister Alexander Kerensky but she and her family were forced to flee the country when the Bolsheviks seized power in 1917.

Flora Benenson as a teenager

Flora Solomon as a teenager (Photo: Wikipedia)

She married a British Jew, Colonel Harold Solomon, entered upper-class left-wing society and became friends with Philby’s family. At a dinner with Simon Marks, one of the creators of Marks and Spencer, when she complained about the way workers were treated, he challenged her to create a welfare department which she did; devising health plans, pension schemes and training programmes for M&S employees.

She also helped find homes for Kindertransport children and during the Second World War helped set up the British Restaurants for people who had been bombed in the Blitz.

She was a socialist and Philby saw her as a kindred spirit. In 1937, over lunch, he told her he was "doing a very dangerous job for peace", adding that he thought "It would be a great thing if she would join the cause". She knew exactly what he meant but she declined, she later said, because, she was "too busy saving the persecuted Jews of Europe". 

It was only three decades later that she voiced her disquiet. By that stage Philby had already come under suspicion, firstly for being friends with two other Cambridge University spies, Guy Burgess and Guy Maclean, and secondly when a Russian spy defected and said the KGB still had an asset in the SIS. He was largely protected by Elliott, who had secured him a job as the Observer’s Beirut correspondent. While he was there, he was working for the SIS and the KGB.

Everything changed when, in August 1962, at a reception in Israel, Flora spoke to an old friend, Victor Rothschild, a former MI5 officer and member of the House of Lords. She asked him: "How is it the Observer uses a man like Kim? Don’t they know he’s a communist? You must do something."

As a result of that conversation, Mr Rothschild secretly arranged for Flora to be interviewed by MI5 agents. A few weeks later, Elliott went to Beirut to finally get his former friend to confess. The six-part drama focuses on what happened next. 

"MI5 had been hunting him for years and Solomon’s hard evidence of guilt they had always lacked," says writer Mr Macintyre, who adds that he regards her to be a heroine. "By denouncing Philby when she did, she changed the course of British history. Had she not done so, this country’s most notorious traitor would probably have got away with it."

After being unmasked as a Soviet agent in January 1963, Philly defected to Moscow, where he remained until his death in 1988.