This distinguished British war film details the exploits of celebrated Royal Navy frogman Lieutenant Lionel "Buster" Crabb (no, not the movie star). He's played here by Laurence Harvey, whose explosive temperament is a perfect match for Crabb's volatile character. The underwater shooting (by Egil Woxholt) is well done and the plot has more excitement than many fictional tales. Reliable Michael Craig plays Crabb's partner, while stern John Clements represents the Admiralty. The saga is shot through with a rich vein of humour, a credit to the creative talent of writer/director William Fairchild. Lovely Dawn Addams is the female lead, but in British films of this period the ladies didn't get much of a look in.

The Mediterranean, 1941/42 - Axis forces are using frogmen and manned torpedoes to attack previously impregnable harbours. The Allied forces need to come up with something to answer this threat, which they find in the form of Lt. Lionel "Buster" Crabb.