•
Viola Prettejohn as Finn, an outcast teenage girl who sets out to investigate the infection. •
Lewis Gribben as Steff, an anxious teenage boy who teams up with Finn who has feelings for him. •
Jay Lycurgo as Charlie, Steff's best friend and Kelly's boyfriend. •
Buket Kömür as Kelly, Charlie's girlfriend and Janine's granddaughter. •
Sue Johnston as Cecily, an elderly woman who is one of the first to be exposed to the Salvepurian virus. •
Robert Lindsay as Morgan, a scientist who secretly created Salvepurian and tries to stop it from spreading. • Paul Benthall as Frank, an elderly man who becomes infected alongside Cecily. He is also Cecily's temporary love interest. •
Anita Dobson as Janine, Kelly's wild grandmother who gets infected after she is bitten where she becomes murderously careless and savage. • Ava Hinds Jones as Billy, Charlie's older sister who is in the army. •
Robert James-Collier as Michael, Charlie's abusive stepfather. •
T'Nia Miller as Karen, Charlie's mother. •
Ellora Torchia as Gil Lonian, an MP in
Westminster who tries to contain the damage within Dambury. •
Michael Smiley as Colonel Wrollen, an army colonel who secretly caused the Salvepurian truck to crash. •
Johnny Vegas as Jason, Kelly's father. • Suzanne Ahmet as Lorraine, Kelly's mother. •
Sophie Leigh Stone as Wendy, Steff's deaf mother. •
Chris Reilly as Terry, Steff's dim-witted yet caring father. •
Rebecca Humphries as Jane, a young woman who gets bitten and infected. • D’Angelou Osei Kissiedu as Kofi, a boy from
London who
sells drugs to help his sick mother. • Ellie-Mae Siame as Maisy, Charlie and Billy's younger sister who becomes friends with Kofi. She is revealed to be Michael's biological daughter making her half siblings to Charlie and Billy. • Robin Hill as Karl, a crime lord from London. Hill reprises his role from Wheatley's previous movie
Down Terrace. • Gareth Tunley as Jon, Karl's partner. Tunley also reprises his role from Down Terrace. •
John Hollingworth as Sgt Martin Parrenster, an army sergeant who looks for Billy after she runs away. • Maanuv Thiara as Malcolm, Billy's best friend in the army. •
Garrick Hagon as Gabe, an elderly man who becomes infected. •
Mark Monero as Jim, a member of the Dambury Neighbourhood Watch. • Bekir Aslan as Mike, a soldier who is killed when the Salvepurian truck he is driving crashes. • Jack Maddison as Lahro •
Andrew Kazamia as Joseph • Joss Carter as Ciaran • Mark Rainsbury as Policeman Jones == Episodes ==