Mission: Impossible star Simon Pegg will play GCHQ s Head of Operations, Danny Patrick, while
The Trial of The Chicago 7 actor Mark Rylance is taking on the role of John Yeabsley, a Cold War veteran who comes out of retirement to help combat the heightened threat level.
Richardson-Sellers, who played Rebekah Mikaelson / Eva Sinclair in
The Originals, is playing American cyber-analyst Kathy Freeman, who is on attachment from the US National Security Agency.
Hustle and
Mary Queen of Scots star Adrian Lester has been cast as Andrew Makinde, the UK s first Black Conservative Prime Minister, while
The Crown actor Alex Jennings is playing the Head of GCHQ, David Neal.
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