He will play West Hampstead accountant turned campaigner Richard Ratcliffe as he battles to get his British-Iranian wife released from jail.
Narges Rashidi (Gangs of London) co-stars as Nazanin, who was arrested by Iran’s Revolutionary Guard at Tehran airport in April 2016 after taking her toddler to visit her parents.
She was thrown into the country’s notorious Evin prison on false spying charges and held hostage pending an unpaid debt by the British government.
The fact-based drama Prisoner 951 is based on the couple’s yet-to-be released memoir A Yard of Sky; A Story of Love, Resistance and Hope and follows their painful separation and fight to get Nazanin back to the UK.
Fiennes, who has also starred in The Handmaid’s Tale and on stage in Dear England, portrays Richard, running the campaign from their flat in West Hampstead, lobbying successive Government ministers – even going on hunger strike outside the Foreign Office.
Meanwhile, Nazanin endures poor prison conditions, then is placed under house arrest at her parents’ home- until then Home Secretary Liz Truss negotiates her return in March 2022 to be reunited with Richard and daughter Gabriella.
The four-part series is written by Stephen Butchard (This City Is Ours, Five Daughters) and directed by BAFTA award-winner Philippa Lowthorpe (Three Girls, The Crown).
It was filmed on location in Greece and the UK and is set to air on BBC iPlayer and BBC One later this year.
BBC producers say that as well as telling the familiar public story of the couple’s ordeal it will show events behind closed doors.
Nazanin said of writing the memoir, which will be published by Penguin Random House: “In prison, the idea of a ‘yard of sky’ gave me hope and it feels right it becomes the title of our book. Writing it has helped me rediscover some of what it means to be normal again. Richard and I went into this alone, but we survived it together and now we are looking forward to sharing our story.”
Richard Ratcliffe said: “Writing our story has been a process of rediscovery. Writing has allowed us to reflect on how we endured, how we survived, how we found colour and sunlight in our “yard of sky”.

