Episode 1

The longest campaign of World War II was fought in the Atlantic Ocean. Tens of thousands of lives were lost as Hitler’s U-boat fleet hunted in packs, chasing down the Allied convoys that brought vital supplies to Britain.

The port of Derry played a vital role as the United Kingdom’s most westerly base, and it was here that German U-boats were taken at the end of the war to officially surrender before being scuttled off Ireland’s north west coast.

A specialist team of deep-sea divers are now searching for these wrecks, while historians unravel the dramatic clashes and human cost of the opening stages of this epic battle at sea.