James Coburn as Robert Elliot

Lee Grant as Jean Robertson

Harry Andrews as Albert Parsons

Ian Hendry as Alex Hellman

Michael Jayston as David Baker

Christiane Krüger as Christina Larsson

Keenan Wynn as E.J. Farnsworth

Terence Alexander as Business tycoon

Julian Glover as Arnold Pryce-Jones

Philip Anthony as Eliot's Secretary

Mary Larkin as Jean's Secretary

Ewan Roberts as Laboratory Technician

David Swift as Chester Drake

Rolf Wanka as Art Dealer

Ray Callaghan as TV Producer

Ralph Ball as Boy Friend

Brian Tully as Business Man

Michael Nightingale as Business Man

Richard Cornish as Co-Pilot

Susan Majolier as Laboratory Assistant

Carrie Kirstein as Air Hostess