Tom Courtenay

Grandpa

Kit Connor

Jack

Jennifer Saunders

Miss Dandy

David Walliams

Barry

Samantha Spiro

Patricia

Alice Nokes

Shelley

Frankie Fox

Dazza

Michele Dotrice

Miss Trifle

Katy Brand

Miss Verity

Harish Patel

Raj

Ralph Riach

Mr. Willkins

Rafe Spall

Adult Jack (voice)

Elliot Hegarty