Cecil Parker as Professor Canford

George Cole as 'Flash' Harry Cuthbert Edwards

Joyce Grenfell as Sergeant Ruby Gates

Eric Barker as Culpepper-Brown

Thorley Walters as Butters

Irene Handl as Miss Harker-Parker

Dennis Price as Gore Blackwood

Sid James as Alphonse O'Reilly

Julie Alexander as Rosalie Dawn

Lloyd Lamble as Superintendent Samuel Kemp-Bird

Raymond Huntley as Judge Slender

Nicholas Phipps as Major Hargreaves

Lisa Lee as Miss Brenner

John Le Mesurier as Minister of Education

George Benson as Defence Counsel

Elwyn Brook-Jones as Emir

Basil Dignam as Army Officer

Cyril Chamberlain as Army Captain

Michael Ripper as Liftman

Mark Dignam as Prosecuting Counsel

Monte Landis as Octavius

Warren Mitchell as Tailor

Clive Morton as V.I.P.

Wensley Pithey as Chief Constable

Liz Fraser as WPC Susan Partridge

Bill Shine as Usher

Edina Ronay as Lavinia (uncredited)

Erica Rogers as Bobbie (uncredited)