Contemptuous of the fallible police force (Mike has already filched a police hat from an accident scene), two 11-year-old boys - the cold, manipulative Leo, and his weaker, more impressionable friend, Mike - arrange a staged knife fight outside a football stadium with the aid of a bag of stage blood and a real blade.
Derrick O'Connor
Detective Ritchie
Gary Holton
Ken
Richard Thomas
Leo Turner
Peter Clark
Mike Simmonds
Gwyneth Strong
Jan, Ken's Girlfriend
Caroline Embling
Susan, Leo's Sister
Jack Douglas
Senior Police Officer
Billy Colvill
Williams
P.H. Moriarty
Police 1
Richard Hope
Police 2
Niall Padden
Police 3
John Mulcahy
Police 4
Terry Paris
Police 5
Neil Cunningham
School Masters 1
George Costigan
School Masters 2
Stewart Harwood
School's Security Guard
Tammi Jacobs
School 1
Daniel Peacock
School 2
Paul Mari
School 3
Mel Smith
Disco Doorman
C.P. Lee
Club Manager
Jimmy Hibbert
Disco 3
Kim Taylforth
Disco 4
Nula Conwell
Ken's Gang 1
Madeleine Church
Ken's Gang 2
Pete Lee-Wilson
Ken's Gang 3 (as Peter Wilson)
Gary Olsen
Ken's Gang 4
Jesse Birdsall
Ken's Gang 5
Roger Lloyd Pack
Hospital Doctor
Brenda Fricker
Nurse
June Watson
Nurse
Colin Campbell
Conductor
Julian Hough
Reporter
Geraldine James
Ritchie's Wife
Richard Beckinsale
Detective Ritchie (uncredited; Died before filming completed)