Martin Clunes as John George Haigh

Keeley Hawes as Gillian Rogers

Richard Hope as Dr. Archie Henderson

Celia Imrie as Rose Henderson

Rowena Cooper as Mrs. Durand-Deacon

John Flanagan as Arnold Burtin

Terence Beesley as DS Heslin

Matyelok Gibbs as Mrs Constance Lane

Barbara Marten as Emily Haigh

Geoff Holman as John Haigh Senior

Christopher Town as John George Haigh (as a boy)

Ken Drury as Mr. Greig

Neil McKinven as Donald McSwan

Claire Nielson as Amy McSwan

Donald Douglas as William McSwan

Christopher Ettridge as Steven Rogers (as Chris Ettridge)

Sally Carman as Betty

Duggie Brown as Morrison

Emma Cooke as Mrs Louisa Bird

Paula Stockbridge as Mrs Kirkwood

Amanda Haberland as Sgt. Lambourne

Charles De'Ath as Sgt Symes

Geoff Oldham as Magistrate

Randal Herley as Elderly Resident

Eamonn Riley as Mr Parry

Nick Chadwin as Veterinary Surgeon