The title might lead one to expect that the boat is a main player in this engaging spy drama. In fact, there is less of it than scenes in London and thereabouts as the Intelligence service seeks the key to a Nazi spy ring which, with the war just over, is trying to grasp control of atomic-bomb secrets. So much happens in this film that there is scant time to dwell on the plausibility of all the twists. As much as anything, it is all carried along by brilliant character acting: suave Robert Newton gets away with some double entendres in talking with Guy Middleton, whose moustache is a character in its own right, while a brief turn by Wildrid Hyde-White makes a taxi driver even more churlish than the trade's general reputation. Sad to say, the charming Muriel Pavlow died last year and almost comes a cropper here, in a well-depicted lodging house, until a telephone call chances to raise the alarm: indeed, it is surprising how much of the film takes place on the telephone. Great entertainment, intelligently done, with the scenes in the Dublin hotel lobby an object lesson in how to manage extras.