This location doubles for the sequences which took actually place at Arlington National Cemetery in Virginia (US) where Kim meets with his Russian handler having found out that Donald in on the list of suspects for being the spy in the British Embassy in the US. They then meet again soon afterwards. It is at this point that Kim is told he must expose Donald as the spy and that both Donald and Guy should be recalled to Moscow. Kim is devastated as their moto has always been that they either stood, or they fell, together as one, but he has no choice.

Whilst exact scene information could not be verified, they would have been shot during the early part of the series.

There are a couple of village scenes which may have used Flaunden, or private houses there, as backdrops. One is when Anthony and Kim talk privately in the rain on the way to Bletchley - they think they are suspected by Moscow of being double agents. Other scenes include Donald’s home, which was actually in Kent in real life, where he lives with his wife Melinda (Anna-Louise Plowman who is actually Toby Stephens’ wife). The final scene is where Donald and Guy know they are about to be discovered and make a run for the coast. Only just in time they drive past The Ship pub and their pursuer and ultimately escape to Moscow where their intention is to defect – their emotions at leaving their beloved England and their friends and family behind is runs high in these scenes.

Interior scenes for the Cambridge Halls of Residence were shot here where Kim has an ‘over night female guest’ that he needs to sneak out! Bushey was also used for the court scene where Guy is accused of trying to proposition another man in a toilet. Guy declares his innocence as an Eton and Cambridge man who simply would not lie to avoid prosecution. The judge decides to rely on his word and dismisses the case. A British Intelligence services man is watching from the back of the court room, approaches Guy and asks him to make discreet enquires at the BBC where he is working about the background of some of the staff there – so it begins for Guy. Scenes at the Foreign Office and MI5 may also have been filmed here.

This was used for much of the early story which took place in the early 1930s when the four Cambridge students meet and form what evolves into a lifetime friendship. All four come from privileged backgrounds but have profoundly strong beliefs with regard to equality and opportunity for all regardless of the background in which a person is born. These beliefs ultimately lead them into Communism and the complex lives of secret agents for Moscow. The backdrop of exteriors in these early scenes were shot in Cambridge, although not in the grounds of Trinity College where the four studied in real life. Key scenes include those in the college grounds, the cloisters, a formal meal and where Guy, following graduation, jumps off the bridge into the River Cam completely naked. To Guy this is a gesture of cleansing whereby he is leaving behind the past and embracing the future. When he doesn’t immediately emerge from the river the others become frantic only to find that he has sneaked out and returned to the bridge to do it again! Donald and Kim become caught up in Guy’s enthusiasm and join him on the bridge – they all jump together whilst Anthony laughs below. Given the River Cam was only about 8 feet deep great care had to be taken with this scene. Much later after Donald and Guy defect to Moscow to avoid capture, Anthony returns to Cambridge and recalls that carefree day when idealism and their desire to change the world was paramount to all of them, days when they had no idea of how embroiled they would all become and what effect it would have. Anthony walks on through the grounds and is approached by a man (unknown) who recognises him from his student days. He asks after him and his friends and enquiries as to whether any of them went onto achieve ‘great things’. Initially Anthony declines to answer truthfully but then turns back to the man and says that they ALL went onto achieve great things; he then walks on nostalgically through the college grounds in the final scene.