S04 E01. The ABC Murders.

First broadcast 5th January 1992.

Poirot starts receiving mocking letters with allusions to crimes-to-be, signed "ABC".

David Suchet as Hercule Poirot
Hugh Fraser as Captain Hastings
Philip Jackson as Chief Inspector Japp
Donald Sumpter as Cust
Donald Douglas as Franklin Clarke
Nicholas Farrell as Donald Fraser
Pippa Guard as Megan Barnard
Cathryn Bradshaw as Mary Drower
Nina Marc as Thora Grey
David McAlister as Inspector Glen
Vivienne Burgess as Lady Clarke
Ann Windsor as Miss Merrion
Michael Mellinger as Franz Ascher
Miranda Forbes as Mrs Turton
Peter Penry-Jones as Superintendent Carter
Lucinda Curtis as Mrs Marbury
Jeremy Hawk as Deveril
Allan Mitchell as Dr Kerr
Philip Anthony as Doctor
Andrew Williamson as Man in Library
John Breslin as Mr Barnard
Clifford Milner as Constable
Claude Close as Doncaster Sergeant
Alex Knight as Andover Sergeant
David Fox as Scotland Yard Sergeant (as David Richard-Fox)
Campbell Graham as Mr. Downes
Gordon Salkilld as Commissionaire
Norman McDonald as Mr Strange
Jane Birdsall as Nurse
Pat Gorman as Desk Sergeant
Tony Red Richards as Librarian