Neil
Catherine
Ray
Grant
James Cleverill
Headmaster
Fenella
Rosie
Miss Pringle
Fiona
Dennis the Dog
Dennis the Dog (voice)
Chief Alien (voice)
Nasty Alien (voice)
Salubrious Gat (voice)
Scientist Alien (voice) / Van Driver
Kindly Alien (voice)
Steve
Canteen Lady
Sandwich Girl
Lavender
Self (as Professor Brian Cox)
Policeman
Reporter
Author
Mr. Eriksson
Police Inspector
Security Man
Newsreader
Documentary Voice (voice)
Alien Computer Voice (voice) and Señorita Lopez
Mortician
Bank Robber
Ray Worshiper
Ray Worshipper (as Debbie Nash)
Pink Policeman
Baby
Party Guest (uncredited)
Photographer (uncredited)
Race Goer (uncredited)
Passerby (uncredited)
Zombie (uncredited)
Celebrity (uncredited)
Book Launch Guest (uncredited)
Ray Worshipper (uncredited)
School Boy (uncredited)
Father (uncredited)
Schoolboy (uncredited)
Man at Party (uncredited)