During WWII, Britain was absolutely reliant on maritime trade for its survival and therefore the protection of its merchant fleet became an issue of paramount importance. Featuring the filmed memories of convoy veterans this is the story of one of WWII's most pitiless theatre of operations, where men lived in constant fear of the unseen dangers of the deep. The program also uses 3D graphics and animation to show the realities of a submarine attack and mechanics of the ships defences. Leading maritime and military experts are also featured.
