Alec Guinness
Professor Marcus
Cecil Parker
Claude, alias 'Major Courtney'
Herbert Lom
Louis, alias 'Mr. Harvey'
Peter Sellers
Harry, alias 'Mr. Robinson'
Danny Green
'One-Round', alias 'Mr. Lawson'
Katie Johnson
Mrs. Wilberforce
Jack Warner
The Superintendent
Philip Stainton
The Sergeant
Frankie Howerd
The Barrow Boy
Madge Brindley
Large Lady (uncredited)
