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Explores the desperate struggle for survival on a hostile ocean during the longest and bloodiest battle of the Second World War.
Seasons
Episode 1
The Grey Wolves
2h 15m
New testimony from British sailors and the U-boat men who hunted them, plus archive material and dramatic reconstructions, illustrate the threat from Churchill's one fear, the hidden enemy under the sea.
Episode 2
Keeping Secrets
2h 15m
In the first 18 months of war, German U-boats sank more than three million tons of shipping. Eyewitness testimony, archive film and reconstructions illuminate the story of how Allied intelligence fought back against the killers in the deep, helped by the seizure of an Enigma code machine and cipher material.
Episode 3Latest episode
The Hunted
2h 15m
In the first three years of war, German U-boats threatened to starve Britain into submission, but by the spring of 1943 the tide had turned and the hunter had become the hunted. Eyewitness testimony, archive film and reconstructions illuminate the remarkable story of how, in just months, the Allies destroyed the U-boat fleet.
