Derek Nimmo as Lord Southmere

Hugh Burden as Haines

Bernard Bresslaw as Fan Choy

Helen Hayes as Hettie

Joan Sims as Emily

Deryck Guyler as Harris

Clive Revill as Quon

Molly Weir as Scots Nanny

Max Wall as Juggler

Natasha Pyne as Susan

Joss Ackland as B.J. Spence

Peter Ustinov as Prince John/ Hnup Wan ''Hunp''

Jon Pertwee as Colonel

Joan Hickson as Mrs Gibbons

Amanda Barrie as Mrs BJ Spence

Percy Herbert as Mr Gibbons

Arthur Howard as Thumley

John Laurie as Jock

Max Harris as Truscott

Andrew Dove as Lord Castleberry

Frank Williams as Dr. Freemo

Aimée Delamain as Millicent

Roy Kinnear as Superintendent Grubbs

Leonard Trolley as Inspecter Eppers

Joe Ritchie as Cabbie

Angus Lennie as Hamish

Kathleen Byron as Colonel's Wife

Lucy Griffiths as Amelia

John Bardon as Bookmaker

Jane Lapotaire as Miss Prescott

Richard Pearson as Sir Geoffrey

Michael Elwyn as Haycock

Anthony Sharp as Home Secretary

Wensley Pithey as Bromley

Peter Madden as Sanders

Erik Chitty as Museum Guard