Bob Peck
— Detective Sergeant Cooper
Miranda Richardson
— Dr. Sarah Blakeney
Douglas Hodge
— Jack Blakeney
Trudie Styler
— Joanna Lascelles
Beth Winslet
— Ruth Lascelles
Siân Phillips
— Mathilda Gillespie
Virginia McKenna
— Violet Orloff
Paul Brooke
— Duncan Orloff
Miles Anderson
— Detective Inspector Harmer
Hugh Bonneville
— Tim Duggan
Finbar Lynch
— Dave Hughes
Alan MacNaughtan
— James Gillespie
Alan Williams
— Bob Spede
Christine Moore
— Jenny Spede
Clare Clifford
— Headmistress
John Pirkis
— Sir William Cavendish (as John Duval)