Michael Wilding is a pleasure to watch in a less serious part, especially alongside a very good Hugh Williams, making this a pretty agreeable espionage film set during the war. Stewart Granger appears as the ship’s captain transporting them (along with James Mason) to France, where they need to collaborate with the Resistance to obtain information about some concealed Nazi plans. Calling it a thriller feels like an overstatement; it's more of a gentle comedy—the acting and tempo are easygoing, there's virtually no sense of danger whatsoever, and the conclusion, while having a bit more action than what came before, feels almost perfunctory with its explosions. The rapport between the actors is definitely one of the film’s strengths, as is the connection between Williams and Carla Lehmann ("Michèle"), who brings in just a touch of suspense. Herbert Lom and Karel Stepanek also contribute, bringing some flair to the uncomplicated plot. It does feel somewhat like propaganda, and it runs about fifteen minutes too long, but overall it's an agreeable film featuring a group of capable performers.

Source on TMDB