Robert Beatty

Bob Beacham

Rona Anderson

Mary Game

Clifford Evans

Tom Harmon

Edward Lexy

Det. Insp. Charlton

Olga Lindo

Olive Tavy

Daphne Padel

Self - The Twenty Questions Team

Jeanne De Casalis

Self - The Twenty Questions Team guest artiste

Jack Train

Self - The Twenty Questions Team

Stewart MacPherson

Self - The Twenty Questions Team

Norman Hackforth

Self - The Twenty Questions Team 'Mystery Voice'

Richard Dimbleby

Self - The Twenty Questions Team

Harold Scott

Maurice Emery KC

Liam Redmond

Echo News editor

Homi Bode

Mohammed Ali

Kynaston Reeves

Gen. Maitland

Sonya O'Shea

Stewart MacPherson's secretary

Frederick Leister

Police Commissioner

Wally Patch

Police Officer 'Tiny' White

John Salew

John Grimshaw

Gordon McLeod

Record News editor

Philip King

Cheshire Cheese waiter

Arthur Young

Doctor

Merle Tottenham

Mrs. Tavy's Neighbour (uncredited)

Meadows White

Frederick 'Ricky' Tavey (uncredited)