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 operate under the noses of the security services for so long remains a mystery. But Mr Burke noted: 'Female spies have been around since Biblical times. Her ability to escape detection had absolutely nothing to do with the fact that she was a woman, as is claimed in the film. 'The film-makers are trying to portray her as a feminist icon so she has more sympathy with modern audiences. It's a kind of propaganda.' 4. The film: In a dramatic finale, Judi Dench's character admits passing British atomic secrets to the Russians, but adds: 'I'm not a traitor. I wanted everyone to share the same knowledge, because only that way could the horror of another world war be averted. 'And I think if you look back at history, you'll see I was right.' She appears distressed and confused while reporters shout questions and bystanders heckle her. Then her son stands beside her and says: 'Mrs Stanley has nothing to be ashamed of. She has made real something which we all talk about but have no idea how to achieve: peace.' The facts: Mrs Norwood really said: 'I did what I did not to make money but to help prevent the defeat of a new system which had, at great cost, given ordinary people food and fares which they could afford, given them education and a health service.' In other words, Mr Burke said, she was giving the world 'a watered-down version' of her Marxist beliefs. 'What she was really saying is that she was spying to promote Communism and she wasn't sorry,' he said. In reality, he added, Mrs Norwood put in a self-assured performance at the press conference. 'She was a highly professional spy,' he said. 'When she addressed the journalists gathered in her front garden, she wasn't harangued in the way that is shown in the film. She was dressed in her Sunday best and read her statement clearly and without a trace of nerves. 'You could have heard a pin drop,' he added. 'She was in complete control and absolutely enjoying herself. As a spy, she was enjoying her moment in the limelight.' Experts who knew Mrs Norwood's career intimately say that she was a lifelong Marxist who volunteered her services to Russia in 1934 via a KGB spy she knew through family connections While working at the BNFMRA (pictured) as a secretary, Mrs Norwood copied top secret documents and handed them to the Russians, including details of Britain's atomic technology in the film her character 'Joan Stanley' admits 'passing information to the Soviets in the 1940s from the BNFMRA in London (pictured) which accelerated their ability to build an atomic bomb 5. The film: 'Joan Stanley' admits 'passing information to the Soviets in the 1940s which accelerated their ability to build an atomic bomb'. After Russia became a nuclear power, however, no further espionage is portrayed. The facts: Mrs Norwood continued to give the Russians state secrets for decades after they tested their first nuclear bomb in 1949. Working as a secretary at Britain's secret nuclear research facility BNFMRA, she was an active spy until she retired in 1972. She even extended her sphere of operation to work with another top KGB agent, Gordon Lonsdale of the Portland Spy Ring. According to one former MI5 officer, Mrs Norwood is thought to have passed important jet engine technology to the Russians. 'Spying is not just about military secrets and weapons,' the former officer said. 'Sometimes technology to boost an enemy economy can be just as dangerous.' 6. The film: Dame Judi's character is depicted as a brilliant nuclear physicist at Cambridge University, blazing a trail as one of the few female students at the time. She is shown as a member of Kim Philby's glamorous Cambridge Spy Ring. After graduation, she is headhunted by the BNFMRA and solves a number of scientific riddles, to the astonishment of male researchers. The facts: Mrs Norwood never visited Cambridge in her life. She studied Latin and Logic at the University College of Southampton and dropped out after a year. 'She got away with it because she was a demure secretary, able to sit at the back of a room unnoticed, taking notes,' Mr Burke said. 'When typing them up, she produced a carbon copy for the Russians. Occasionally, she would use a camera to photograph documents. 'The need to dress her up as a woman with intellectual breeding is revealing.' The former MI5 officer added: 'It's much sexier to have a plucky, brilliant woman at Cambridge doing the spying than a poorly-educated secretary from Bexleyheath. 'Of course, this is the sort of thing that happens in films. But it builds her up into a heroine when she really was a traitor.' MailOnline spoke to Mrs Norwood's biographer David Burke and a former MI5 agent who both said the film has glorified her role in the Cold War and brushed under the carpet her treacherous communist motivations In the film, Mrs Norwood, Judi Dench (left) and Sophie Cookson (right) is presented as an innocent undergraduate from an ordinary English family who is reluctantly persuaded to work for the KGB by a handsome Russian agent and his friends. In reality she was a lifelong Marxist who volunteered her services to Russia in 1934 via a KGB spy she knew through her family 7. The film: 'Joan Stanley' is portrayed as a sexually promiscuous Soviet agent who has affairs with a number of men, including her boss, Professor Max Davies (played by Stephen Campbell Moore). The facts: Mrs Norwood married her husband, Hilary, in 1934 and by all accounts had a very happy marriage, nursing him dutifully when he fell ill and died of liver cancer. She was entirely devoted to her family. Mr Burke said: 'Sexual exploitation of characters drawn from real life remains the order of the day in Hollywood, especially if money and reputations are to be made. No sex, no spy film. 'In most films it wouldn't matter, but in this case the whole thing is in the service of pro-Russian propaganda.'All rights reserved for this news site dailymail and under his responsibility