Sly and dry intelligence agent Harry Palmer is tasked with investigating British Intelligence security, and is soon enmeshed in a world of double-dealing, kidnap and murder when he finds a traitor operating at the heart of the secret service.

• The Rank Organisation
• Lowndes Productions Limited
• Michael Caine
• Nigel Green
• Guy Doleman
• Sue Lloyd
• Gordon Jackson
• Aubrey Richards
• Frank Gatliff
• Thomas Baptiste