Keeley Hawes plays a member of the post-war Civil Service who is convinced a colleague is not who she seems in the trailer for her first drama after Bodyguard.
The actress is part of a star-studded cast in Traitors, about a young woman who agrees to spy on her own government for the Americans.
The Channel 4 drama is Boardwalk Empire creator Bash Doran’s first original commission for British TV.
Directed by Dearbhla Walsh, it also stars The Shape Of Water actor Michael Stuhlbarg, Ordeal By Innocence’s Luke Treadaway and Stephen Campbell Moore.
Hawes plays Priscilla, who becomes concerned that new recruit Feef Symonds, played by Emma Appleton, is not who she seems.
The younger woman joins the Civil Service in 1945, just as the Labour Party sweeps to victory, defeating Winston Churchill in an unexpected landslide.
Her ambition to make something of her life goes unrecognised by her family, and is further complicated by her American lover.
She agrees to spy on her own government for the Americans, who want to make sure England’s burgeoning Socialist ambitions don’t play into Soviet hands.
The cast also includes Brandon P Bell and Matt Lauria and the series will air on Channel 4 later this year.