Theo Stevenson

Horrid Henry

Anjelica Huston

Miss Battleaxe

Parminder Nagra

Miss Lovely

Mathew Horne

Dad

Siobhan Hayes

Mum

Richard E. Grant

Vic Van Wrinkle

Prunella Scales

Great Aunt Greta

David Schneider

Soggy Sid

Kimberley Walsh

Prissy Polly

Billy Kennedy

Weeping William

Noel Fielding

Ed Banger

Jo Brand

Demon Dinner Lady

Helen Lederer

Rich Aunt Ruby

Rebecca Front

Miss Oddbod

Helena Barlow

Sour Susan

Frank Kauer

Spotless Sam

Tyger Drew-Honey

Stuck-Up Steve

Dominic Wood

2C4S Presenter 1

Richard McCourt

2C4S Presenter 2

Zac Gabriel Werb

Tidy Ted

Keely Cat Wells

Alice

Kia Pegg

Vicious Vicky

Freddie Rose

Schoolboy (uncredited)