Terry-Thomas as Cadogan de Vere Carlton-Browne

Peter Sellers as Prime Minister Amphibulos

Luciana Paluzzi as Princess Ilyena

Ian Bannen as Young King Loris

Thorley Walters as Colonel Bellingham

Raymond Huntley as Foreign Secretary Tufton-Slade

Miles Malleson as Resident Advisor Davidson

John Le Mesurier as Grand Duke Alexis

Marie Lohr as Lady Carlton-Browne

Kynaston Reeves as Sir Arthur Carlton-Browne

Ronald Adam as Sir John Farthing

John Van Eyssen as Hewitt

Nicholas Parsons as Rodgers

Irene Handl as Mrs. Carter

Harry Locke as Gaillardian commentator

Basil Dignam as Security Officer

Sam Kydd as Signaller

Robert Bruce as Major Miller

John Glyn-Jones as Newsreel Interviewer

Marianne Stone as Woman In Cinema

Margaret Lacey as Onlooker

Robert S. Young as Archivist

Kenneth Griffith as Sir John's Assistant (uncredited)

Mario Fabrizi as Deputy Minister (uncredited)

Katherine Keeton as Dancer

Bruno Barnabe as Maître d'

Max Brimmell as Waiter

Nicholas Bruce as King Loris' Equerry

Andre Charisse as Russian Minister

Alexis Chesnakov as First Russian Scientist

Anthony Chinn as Dignitary at Royal Pageant

Maurice Colbourne as First Official

Fiona Davie as

John Drake as

James Dyrenforth as Admiral

Rex Garner as Hotel Porter Removing Flowers

George Holdcroft as Security Man at Ministry

Julie Hopkins as Dancer

Harold Kasket as

Kaplan Kaye as

Dan Lester as US Delegate at UN Conference

Fred Machon as Delegate at UN Conference

Marne Maitland as Archipolagos

Alf Mangan as Delegate

Mark Mileham as Child

Patrick Mynhardt as British Soldier

Michael Partridge as Commandos Captain

Anthony Pendrell as Official

Frank Phillips as BBC Newsreader

Geremy Phillips as Italian Guard

Bill Rayment as Second Russian Scientist

Tony Spears as Delegate at UN Conference

Guy Standeven as Civil Servant

Austin Trevor as Secretary General

Jim Tyson as US Delegate at UN Conference

James Ure as Delegate at UN Conference

Ian Wilson as Onlooker

Michael Ward as Hotel Manager