Alec Guinness
Professor Marcus
Acting
Cecil Parker
Claude, alias 'Major Courtney'
Acting
Herbert Lom
Louis, alias 'Mr. Harvey'
Acting
Peter Sellers
Harry, alias 'Mr. Robinson'
Acting
Danny Green
'One-Round', alias 'Mr. Lawson'
Acting
Katie Johnson
Mrs. Wilberforce
Acting
Jack Warner
The Superintendent
Acting
Philip Stainton
The Sergeant
Acting
Frankie Howerd
The Barrow Boy
Acting
Madge Brindley
Large Lady (uncredited)
Acting
Hélène Burls
Hypatia (uncredited)
Acting
Kenneth Connor
Cab Driver (uncredited)
Acting
Michael Corcoran
Burglar (uncredited)
Acting
Harold Goodwin
Parcels Clerk (uncredited)
Acting
Fred Griffiths
Junk Man (uncredited)
Acting
Lucy Griffiths
Miss Pringle (uncredited)
Acting
George Hilsdon
Security Van Driver (uncredited)
Acting
Vincent Holman
Station Master (uncredited)
Acting
Stratford Johns
Security Guard (uncredited)
Acting
Sam Kydd
Second Cab Driver (uncredited)
Acting
Edie Martin
Lettice (uncredited)
Acting
Jack Melford
Detective (uncredited)
Acting
Arthur Mullard
(uncredited)
Acting
Ewan Roberts
Constable (uncredited)
Acting
George Roderick
Radio Car Policeman (uncredited)
Acting
John Rudling
Nervous Man (uncredited)
Acting
Leonard Sharp
Pavement Artist (uncredited)
Acting
Peter Williams
Detective at Parcels Office (uncredited)
Acting
Neil Wilson
Policeman (uncredited)
Acting
Phoebe Hodgson
Constance (uncredited)
Acting