Richard Chamberlain

George Gordon, Lord Byron

John Mills

Canning

Margaret Leighton

Lady Melbourne

Pamela Brown

Lady Bessborough

Silvia Monti

Miss Milbanke

Ralph Richardson

George IV

Laurence Olivier

Duke of Wellington

Caterina Boratto

Peter Bull

Minister

Roy Stewart

Black Pug

Michael Wilding

Lord Holland

Charles Carson

Potter

Sonia Dresdel

Lady Pont

Nicholas Field

St. John

Felicity Gibson

Girl in Blue

Robert Harris

Apothecary

Richard Hurndall

Radical

Paddy Joyce

Irish housekeeper

Bernard Kay

Benson

Janet Key

Miss Fairfax

Mario Maranzana

Coachman

Robert Mill

ADC to Wellington

Norman Mitchell

Restaurant functionary

John Moffatt

Murray

Trevor Peacock

Agent

Maureen Pryor

Mrs. Buller

Fanny Rowe

Lady Holland

Stephen Sheppard

Buckham

Ralph Truman

Admiral

Jack Carter

Guest (uncredited)