This is an excellent early 50s murder mystery thriller set in Venice with some great set pieces and beautiful and at times striking on location photography...much better than the overrated Venice filmed in "Don't Look Back".
Great mood - a marrying of post war paranoia ( Venice is close to the then disputed city of Trieste - between the West and communist Yugoslavia) and political intrigue which reflected the chaotic state of Italian politics at the time.
Ralph Thomas ( brother of Gerald of Carry On fame and who edited this film) made his fame with the "Doctor" comedy films starring Dirk Bogarde and Iron Petticoat with Bob Hope and Katharine Hepburn but he also made quite a few well above average middle budget suspense / drama films - Campbell's Kingdom (1957), Checkpoint (1956), Above Us the Waves (1955), Appointment with Venus (1951), The Clouded Yellow (1951), of which this is one of the best. The climactic chase is excellent.
Good performance from the ever reliable Richard Todd and a nifty small role for Sid James.Excellent music by Nino Rota ( Godfather, La Strada, La Dolce Vita, 8 1/2) also.
A underrated gem.