David Tennant Alexander Litvinenko Actor, Executive Producer Margarita Levieva Marina Litvinenko Actor Mark Bonnar DS Clive Timmons Actor Neil Maskell Brent Hyatt Actor Barry Sloane DS Jim Dawson Actor Daniel Ryan DAC Peter Clarke Actor Richard Pepper DCI Duncan Ball Actor Stephen Campbell Moore Ben Emmerson QC Actor Simon Paisley Day Sir John Scarlett Actor Sam Troughton DI Brian Tarpey Actor Jim Field Smith Director, Executive Producer George Kay Writer, Executive Producer Chris May Producer Patrick Spence Executive Producer