Dirk Bogarde as Sebastian

Susannah York as Rebecca Howard

Lilli Palmer as Elsa Shahn

John Gielgud as Head of Intelligence

Janet Munro as Carol Fancy

Ronald Fraser as Toby

Margaret Johnston as Miss Elliott

Nigel Davenport as Gen. Phillips

John Ronane as Jameson

Hayward Morse as Gavin

Donald Sutherland as Ackerman

Ann Beach as Pamela

Susan Whitman as Tilly

Ann Sidney as Naomi

Veronica Clifford as Ginny

Louise Purnell as Thelma

Portland Mason as 'UG' Girl

James Belchamber as Man with Dog

Charles Farrell as Taxi Driver

Charles Lloyd Pack as Chess Player

Alan Freeman as TV Disc Jockey

Jeanne Roland as Randy

Lynn Pinkney as Joan

Sally Douglas as Uncredited

Stuart Hoyle as Uncredited