to Forsyth that they produce a film together. They hired George Axelrod to write a script and John Frankenheimer to direct, but were unable to raise finance. Axelrod and Frankenheimer left the project, Forsyth wrote the script himself and they got a new producer and director. Locations Much of the film was shot in the Heelands district of Milton Keynes, the main house featured is on Tranlands Brigg, Heelands, Milton Keynes. Scenes set on the London Underground were shot at Charing Cross, Green Park, and Aldwych stations. Colchester Station was also used in one scene, with star Michael Caine filmed standing on the tracks. For some of the interiors, rooms of King's College London on the Strand were used. The "RAF Baywaters" scenes were filmed at the now defunct RAF Upper Heyford as a take on the real life RAF Bentwaters. Filming also took place in Finland. Towards the end of the film, the car chase in Ipswich is actually shot in Chelmsford on the A1016 Chelmer Valley bypass which at the time was newly built. One shot shows helicopters flying under the Orwell Bridge which is often considered a local landmark. Eastbourne Mews, W2, was used as the filming location for John Preston's (Michael Caine) house. Differences from the novel The film opens with the killing of Kim Philby, who has already planned the operation, because he knows too much. In the book, he remains a key figure. The film begins with Preston breaking into Berenson's house to expose him as a traitor. In the novel, Jim Rawlings, a professional thief, robs Berenson's flat of jewellery. In the process, he discovers illegal copies of classified documents in a briefcase. As a patriotic citizen, he takes them and sends them anonymously to MI5. The character of Rawlings is omitted from the film and the side plot of the disposal of the stolen jewellery is not pursued. In the film, the jewellery is taken by Preston, and returned to Berenson by Irvine. In the novel, the jewellery is broken down by Rawlings's fence and later taken from the diamond polisher working for the fence after he is tortured and killed. Berenson's contacts have a replica made of the jewellery using zirconium stones and later permanently deposits them with his bank. The political plot of the book to enable the Labour Party to win the general election and allow for a communist