Despite obviousness of many plot elements within this work directed by renowned cinematographer Jack Cardiff, it is quite possible to enjoy the film for its merits that include expected polished camera-work and lighting, but also superlative design, plainly a result of competent research, and atmospheric settings about Windsor Castle, to the benefit of a somewhat unfocused crime melodrama involving murder in the normally staid world of philately. Action opens in a flat close by the Castle with a young woman, fresh from a shower, being bludgeoned to death, over two dozen blows to the face making her corpse essentially unrecognizable, and when Detective Inspector Matthews (James Booth) launches an investigation he learns that the deceased was one of a pair of decorative and identical twins, performed by Francesca Annis, the surviving sister, Delphi, employed by their guardian, a prominent stamp collector, with the titular item, a piece of enormous value, being target of a plot to steal it, this somehow connected with the homicide. Filmed at London's Pinewood Studios complex and on location in the vicinity of Windsor Castle, including the House on the Bridge Restaurant atop Windsor Bridge, the windows of which offer an agreeable view of the Royal edifice (enjoyed here at lunch by Matthews and Delphi), the film suffers from credibility factors and an oddly structured use of flashbacks, but a John Scott score is reasonably effective (there is a seamless inclusion of police sirens!), and Cardiff leads his players well. There is not a weak portrayal from among the cast, with even the monochromatic Annis being largely believable, Booth and Nicky Henson providing strong turns as the case investigators; Joss Ackland gains acting honours as Jones, supervising police official in the matter.