The story follows Charlie Cox as Charles Thoroughgood, a spy working in London during the 1970s. The son of another revered spy, Thoroughgood is striving to live up to his father’s reputation; to continue his legacy. His exploits take him into contact with a Russian diplomat named Victor Koslov (Andrew Scott), and as Thoroughgood tries to work his Russian target, he finds that it’s Koslov who does a number on him, and the Russian’s revelations about his father turn everything he thought he knew about himself and his life upside down.

Charlie Cox (Stardust) makes for a wonderful lead. He’s charming and charismatic, and expertly portrays the increasing sense of confliction within the man as the Thoroughgood family legacy is called into question. Andrew Scott as his vulnerable counterpart also impresses.

Sherlock’s Scott provides a lesson in understatedness that couldn’t be further from his flashy turn as Moriarty, even as he affects a mostly convincing Russian accent throughout. Deeper into the cast, and Romola Gari is also involved (this is a BBC Two drama, after all) as Thoroughgood’s love interest, and Cox and Gari sizzle their way through every interaction – their chemistry is electric.

The script, by Paula Milne, is extremely well written, and never, ever obvious. The dialogue is natural and if some beats of the plot might not be entirely unexpected, the interactions between characters are never clichéd. As director, Pete Travis returns from Hollywood (where he directed the well-received Dredd reboot) to the small-screen, and does so with aplomb; he directs masterfully.

Some of the shot compositions are extremely eye-catching, and Travis knows exactly when to let things breathe, and when to ratchet up the suspense. The result is a riveting piece of work, both in the quiet, introspective moments and in the more exciting spy-fare. Legacy is a very well-paced piece of work, with a soundtrack perfectly weighted to compliment the action.

Where do a man’s loyalties lie when his entire life is thrown upside down? With his country? His family? His lover? Himself? These are the questions Thoroughgood has to deal with, and with Cox’s assured performance, it’s fascinating to watch him wrestle with them.

Legacy is a subtle, intelligent and captivating film, tackling the over-arching themes of the Cold War period, but on a very personal level. A supremely classy affair,

Legacy manages to stay true to the rich history of British espionage thrillers, whilst also crafting an identity of its own. Very impressive.

Aired at 9pm on Thursday 28 November 2013 on BBC Two.

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