Ian Hunter

Detective Inspector Gregory

Austin Trevor

Leopold Dryden

Lilian Oldland

Joan Dryden

Henry Kendall

Rodney Fleming

Val Gielgud

Julian Caird

Peter Haddon

Guy Bannister

Betty Ann Davies

Poppy Levine

Jack Hawkins

Herbert Evans

Donald Wolfit

Sydney Parsons

Robert Rendel

Sir Herbert Farquharson

Gordon McLeod

Chief Commissioner

Ivor Barnard

Joseph Higgins (uncredited)

Howard Douglas

Weisskopf (uncredited)

Arthur Hambling

Man on BBC Reception Desk (uncredited)

Bruce Lester

Peter Ridgwell (uncredited)