Richard Attenborough as Percy Boon

Alastair Sim as Mr. Squales

Fay Compton as Mrs. Josser

Stephen Murray as Uncle Henry

Wylie Watson as Mr. Josser

Susan Shaw as Doris Josser

Hugh Griffith as Headlam Fynne

Joyce Carey as Mrs Vizzard

Ivy St. Helier as Connie Coke

Andrew Crawford as Bill

Eleanor Summerfield as The Blonde

Jack McNaughton as Jimmy

Maurice Denham as Jack Rufus

Aubrey Dexter as Mr Battlebury

Henry Hewitt as Verriter

Arthur Howard as Mr Chinkwell

Fabia Drake as Mrs Jan Byl

Sydney Tafler as Night Club Receptionist

Henry Edwards as Police Superintendant

George Cross as Inspector Cartwright

Cyril Chamberlain as Det Sgt Wilson

Edward Evans as Det Sgt Taylor

John Salew as Mr Banks

Russell Waters as Clerk of the Court

Cecil Trouncer as Mr Henry Wassall KC

Kenneth Downey as Mr Veezey Blaize KC

Ivor Barnard as Mr Justice Plymme

Basil Cunard as Foreman of the Jury

Wensley Pithey as 1st Warden

Manville Tarrant as 2nd Warden

Arthur Lowe as Commuter on Train (uncredited)

Ewen Solon as Clerk (uncredited)

Jack May as Bystander (uncredited)

Reg Thomason as Bystander (uncredited)

Myrette Morven as Female Employee (uncredited)

Ewan Roberts as 1st Policeman (uncredited)

Stanley Beard as 2nd Policeman (uncredited)

Leo Genn as Narrator (uncredited)