The new Hollywood blockbuster 'Red Joan', starring Judi Dench and Sophie Cookson, tells the colourful life of KGB spy Melita Norwood, who betrayed Britain to sell secrets to the Kremlin for almost 40 years.
She is portrayed in the film as a sexy, promiscuous, but demure super-spy from Bexleyheath, a feminist heroine who betrayed her country for the sake of world peace.
But the truth and her motivations are much darker, as MailOnline worked with former MI5 officers and Norwood's biographer David Burke to pick apart the film and tell the real story.
What is true is Mrs Norwood was an unassuming secretary at Britain's secret nuclear research facility, the British Non-Ferrous Metals Research Association (BNFMRA).
She copied top secret documents and handed them to the Russians, including details of Britain's atomic technology.
The secret agent, one of Russia's most valued assets, retired in 1972 and was awarded the Order of Lenin in Moscow, together with a KGB pension until her death in 2005.
She was exposed in 1999, by then aged 87 and a widow - but the Government decided not to prosecute her in order to protect other sources and investigations.
Here we reveal how the film has glorified Mrs Norwood's role in the Cold War and brushed under the carpet her treacherous communist motivations.
Hollywood blockbuster 'Red Joan', starring Judi Dench and Sophie Cookson, tells the life of KGB spy Melita Norwood, who betrayed Britain to sell secrets to the Kremlin for 40 years
Mrs Norwood (left) is portrayed in the film by Sophie Cookson (right) as a sexy, promiscuous, but demure spy, a feminist heroine who betrayed her country for the sake of world peace
'Red Joan': the film vs the facts
1. The film: Melita Norwood – called 'Joan Stanley' in the movie – is presented as an innocent undergraduate from an ordinary English family. She is reluctantly persuaded to work for the KGB by a handsome Russian agent and his friends.
The facts: Mrs Norwood was a lifelong Marxist who volunteered her services to Russia in 1934 via a KGB spy she knew through family connections.
'I made the approach,' Mrs Norwood later told her biographer, David Burke. 'I must have thought then, I wonder if any of the work might be useful?'
Mrs Norwood (pictured in her later years) was an unassuming secretary at the UK's nuclear research facility, the British Non-Ferrous Metals Research Association (BNFMRA)
She had come from a deeply Communist background. Her Latvian father, Alexander Sirnis, worked as a Russian translator alongside one of Lenin's most successful spies, Theodore Rothstein. It was his son Andrew who recruited Mrs Norwood.
Her mother, Gertrude Sirnis, was an English Stalinist spy. Her home was used as a secret contact point between Moscow Centre and the British Communist Party (BCP), and was used to recruit British sympathisers to train as wireless operators in Moscow.
Gertrude groomed her daughter for a career in intelligence, even accompanying her to her first meeting with her handler, Andrew Rothstein.
2. The film: Appalled by the loss of life in Hiroshima and Nagasaki, 'Joan Stanley' finally agrees to work for the KGB. No side would dare use the bomb, she argues, if both had it. Later, she is proud of her decision. 'History has proved me right', Dame Judi's character says.
The facts: By the time Hiroshima was bombed, Mrs Norwood had already been spying for 11 years. Her actions had nothing to do with Hiroshima or world peace. She did what she did because she was a fanatical Communist.
'Melita Norwood was a die-hard Communist who proliferated nuclear technology,' ex-MI5 officer Nick Day said.
'There could be no worse betrayal of Britain. The Russians were our sworn enemies. To make matters worse, they could have shared our nuclear secrets with countries like North Korea.
'Mrs Norwood's actions are not something to be celebrated, however trendy it might feel for Russophile film-makers to rewrite history.'
Mr Burke added: 'In the film, Mrs Norwood's communism slips out of sight. The film is simply a dishonest misinterpretation of her life, in order to give some warped credibility to their view that she saved humanity from certain destruction.
'One wonders whether the film-makers believe that nuclear proliferation should be allowed to bring peace to the Middle East?'
Mrs Norwood, called 'Joan Stanley' in the movie and played in her later years by Judi Dench, was exposed as a Russian spy in 1999, by then aged 87 and a widow
Mrs Norwood was in the spotlight when she was outed as a spy for the Kremlin. The Government chose not to prosecute her in order to protect other sources and investigations
3. The film: 'Joan Stanley' escaped detection because she was female. 'Nobody would suspect us,' the character tells a fellow female KGB operative. 'We're women.'
The facts: MI5's Soviet expert at the time, Jane Archer, and its leading counter-intelligence agent, Millicent Bagot, were both women. They did not ignore female KGB agents.
Mrs Norwood's life was made into a book by David Burke who told MailOnline there are a number of inconsistencies in 'Red Joan'
Indeed, MI5 investigated Mrs Norwood no fewer than six times, including an extended probe in 1965.
During the War, she came to the attention of a female MI5 counter-intelligence officer, Mona Maund.
She reported the secretary to her superiors. But the blundering head of B Division, Jasper Harker, who had a reputation for being ‘not very bright’, dismissed these suspicions.
Quite why she was able to