Bill Milner as Will Proudfoot

Will Poulter as Lee Carter

Jessica Hynes as Mary Proudfoot

Jules Sitruk as Didier Revol

Neil Dudgeon as Joshua

Ed Westwick as Lawrence Carter

Anna Wing as Grandma

Tallulah Evans as Jess Proudfoot

Emilie Chesnais as French Teacher

Paul Ritter as Geography Teacher

Adam Buxton as Science Teacher

Adam Godley as Brethren Leader

Asa Butterfield as Brethren Boy

Edgar Wright as Metal Work Teacher

Adam Paul Harvey as Lawrence's Henchman

Atila Emirali as Rambo Double

Louise Jennings as Nurse