Starring Hayley Atwell (Captain America), Rufus Sewell (Zen), Michelle Dockery (Downton Abbey), Michael Gambon (Page Eight) and Charlotte Rampling (Melancholia), the two 90-minute episodes will air on BBC One in late 2012.

Restless will begin filming in South Africa and the UK this summer, directed by Edward Hall (Spooks).

Screenwriter and author, William Boyd, commented: “To have the chance to film a novel like Restless over three hours is the sort of opportunity that only a television adaptation can provide. It represents the most enticing and alluring of possibilities – not only to tell an enthralling story of wartime espionage, love and betrayal but also to lift the lid on one of the last secrets of the Second World War.”

Producer, Hilary Bevan Jones, added: “Restless weaves a great love story within a riveting espionage thriller. Trust, betrayal and the need to escape the past are at the heart of this story; and Will has brought these themes to the screen with great elan.”

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The official synopsis reads: “What becomes of your life when everything you thought was solid and certain about it turns out to be a fantastically complicated lie? This happens to Ruth Gilmartin (Michelle Dockery) when, one day in 1976, her mother Sally (Charlotte Rampling) suddenly tells her she has been living a double life. She is not respectable Sally Gilmartin but in fact Eva Delectorskaya, a spy for the British Secret Service who has been on the run for 30 years.

“Eva’s story begins in Paris in 1939. Eva (Hayley Attwell), a beautiful Russian émigrée, is recruited for the British Secret Service by Lucas Romer (Rufus Sewell), a mysteriously alluring Englishman. As Romer trains Eva to become the perfect spy their love affair begins. When a crucial mission collapses in the USA and Eva finds herself in terrible, fatal jeopardy she knows she has no option but to run and hide – forever. Once a spy always a spy. No-one can be trusted. But now Sally Gilmartin yearns to end her years of restless watching and waiting.

“Thirty years on, the only man who can bring this about is her former lover and spymaster, Lucas Romer, now Baron Mansfield of Hampton Cleeve (Michael Gambon), and the only person she can call on for help is her daughter, Ruth. The final chapter of this epic story of love, duplicity and betrayal is about to end – and who will pay the greatest price remains to be discovered.”

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