The eight-part series is is produced by Kudos Film & Television ('MI-5,' 'Life on Mars') for BBC One and HBO/Cinemax in association with Big Light Productions. It will shoot in Scotland, London and Morocco, and is slated to air on Cinemax in 2012.
Spotnitz will executive-produce along with Alison Jackson, Jane Featherstone and Stephen Garrett from Kudos Film & Television and Christopher Aird from the BBC. Eliza Mellor ('Albert Schweitzer,' 'Derek') produces, and SJ Clarkson ('Heroes,' 'Life On Mars') will direct the first two episodes.
In a statement, Spotnitz said "I'm incredibly excited about the ambition of this series. It's got action on a cinematic scale, huge story twists and turns, and intriguing characters who are both emotionally and morally complex. I can't imagine a better cast, director or production team to bring it all to life."
George plays Sam, who's described as "a highly skilled operative for an elite private intelligence firm, who survives an attempt on her life that may have been orchestrated by members of her own team." Once she's back at work she has to figure out who she can trust and who wants her dead. Rayner plays her love interest and co-worker.
The cast is rounded out by Lex Shrapnel ('Captain America: The First Avenger"), Uriel Emil ('Criminal Justice'), Patrick Malahide ('Game of Thrones,' 'Five Days'), Stephen Campbell Moore ('The Bank Job,' 'The History Boys') and Oscar Kennedy ('Toast').
Follow Catherine on Twitter: @TVClaw.