Bob Peck as Detective Sergeant Cooper

Miranda Richardson as Dr. Sarah Blakeney

Douglas Hodge as Jack Blakeney

Trudie Styler as Joanna Lascelles

Beth Winslet as Ruth Lascelles

Siân Phillips as Mathilda Gillespie

Virginia McKenna as Violet Orloff

Paul Brooke as Duncan Orloff

Miles Anderson as Detective Inspector Harmer

Hugh Bonneville as Tim Duggan

Finbar Lynch as Dave Hughes

Alan MacNaughtan as James Gillespie

Alan Williams as Bob Spede

Christine Moore as Jenny Spede

Clare Clifford as Headmistress

John Pirkis as Sir William Cavendish (as John Duval)