Dirk Bogarde is quite charismatic in this rather daft spy story set at the height of the Cold War. "Whistler" is a struggling writer who is found a job opportunity by the local labour exchange. Arriving at the plush office of glass-maker "Cunliffe" (Robert Morley) and his sidekick "Allsop" (John Le Mesurier) he is dazzled by the enormous £40 per week wage and equally bamboozled that they want to give him such a lucrative job in an industry about which he knows zilch. First assignment is a trip to Communist Czechoslovakia where he is to rendezvous with a fellow glass engineer, and after having exchanged the passwords - hence the film's title - swap books and come straight home. Simple? Well, of course not quite. He has no idea that he is being used by his new boss and that the Czech intelligence service - run by "Simoneva" (Leo McKern) is onto him. That latter man even gets his glamorous daughter "Vlasta" (Sylva Koscina) to drive for the man so they can speedily apprehend him - but, of course, that doesn't quite go to plan either! Finally cottoning on to the nature of his predicament, our hapless "Whistler" has to find a way of making it to the safety of the British embassy before he is found "accidentally having fallen from his luxury hotel window". It's a little bit slapstick and over-scripted, but the assembled cast do add a bit of fun to the leading performance that is maybe more reminiscent of his "Doctor..." films rather than his more substantial roles. That said, fans of British comedy films will recognise just about everyone and it's parody of "James Bond" at times can't go un-noticed. Not great, but worth a watch, I'd say.