Dennis Price

Louis Mazzini / His Father

Alec Guinness

The D'Ascoyne Family: The Duke / The Banker / The Parson / The General / The Admiral / Young Ascoyne / Young Henry / Lady Agatha

Joan Greenwood

Sibella

Valerie Hobson

Edith D'Ascoyne

Audrey Fildes

Mama

Miles Malleson

The Hangman

Clive Morton

The Prison Governor

John Penrose

Lionel Holland

Cecil Ramage

Crown Counsel

Hugh Griffith

Lord High Steward

John Salew

Mr. Perkins

Arthur Lowe

The Reporter

Peter Gawthorne

First Lord Delivering Verdict (uncredited)

Jeremy Spenser

Young Louis (uncredited)

Carol White

Young Sibella (uncredited)

Laurence Naismith

Warder in Jail (uncredited)

Richard Wattis

Defence Counsel (uncredited)