Guest Stars Barry Sloane as DS Jim Dawson Mark Ivanir as Alexander Goldfarb Daniel Ryan as DAC Peter Clarke Temirlan Blaev as Young Anatoly Litvinenko Kayla Meikle as DC Deborah Maxwell Richard Pepper as DCI Duncan Ball Kirsten Foster as Jenny Hyatt Sam Troughton as DI Brian Tarpey Estella Daniels as Dr Onome George Marcus Onilude as Aidan Aleksandar Mikic as Dmitry Kovtun Dan Skinner as James Cairns Ian Conningham as Dr Nick Gent Rad Kaim as Andrey Lugovoy Edward Baker-Duly as Martin Svennson Sarah Naudi as Dr Justine Adams Maggie Evans as Professor Pat Troop Simon Paisley Day as Sir John Scarlett Antonio Magro as Mario Scaramella Kareem Alexander as Michael