Main •
Mark Strong as Daniel Milton, a brilliant surgeon who is willing to provide illegal medical care to fund his covert care of his wife and research into finding a cure for her illness •
Carice van Houten as Anna Willems, a medical researcher and friend of Beth, who had an affair with Daniel in the past and reluctantly assists him with his underground clinic •
Daniel Mays as Lee Simmons, a transport network employee and "
doomsday prepper", who helps Daniel establish an illegal underground clinic •
Catherine McCormack as Beth Milton, Daniel's wife and a medical research scientist, who is suffering from a terminal case of
Lancaster's Disease •
Lily Newmark as Eve Milton, Daniel and Beth's 19-year-old daughter who is studying at university • Tobi King Bakare as Jamie Harris, a fugitive bank robber •
Wunmi Mosaku as Mercy King, the mother of bank robber Sebastian King •
Craig Parkinson as Keith Sullivan, a criminal enforcer and ex-lover of Mercy King •
Chloe Pirrie as DI Karen Hall (series 1) • Ryan McKen as DI (demoted to DS in series 2) Rob Moloney •
Siena Kelly as Michelle Wilson, Jamie's pregnant girlfriend •
Claire Rushbrook as Gloria Wilson, Michelle's mother
Recurring • Theo Solomon as Sebastian King, a bank robber •
Kate Dickie as Eleanor, Beth and Anna's boss •
Anamaria Marinca as Suzanna, an employee at Daniel's hospital who becomes one of his patients •
Turlough Convery as Simon Reynolds • Mark Bazeley as Michael Chander, a fellow doctor and friend of Daniel's •
Sam Hazeldine as Jack Lorean, Anna's boyfriend •
Steffan Rhodri as Jeremy, Lee's manager • Jan Bijvoet as Clive, a criminal connected to the
black market organ trade • Johann Myers as Nick, a criminal connected to the black market organ trade • Ruhtxjiaïh Bèllènéa as Ash Falomo, an activist friend of Eve's •
Rhys Ifans as Gubby, a fixer in London's criminal underworld •
Michael Smiley as Dermot, an associate of Gubby • Michael Akinsulire as Tommy, one of Daniel's patients •
Mandeep Dhillon as DI Kam Skinner, Rob's cousin
Guest •
Donald Sumpter as George, a clinic patient •
Martin McCann as Cormac, a clinic patient •
Marion Bailey as Ingrid •
Jo Hartley as Professor Kirby ==Episodes==