Author Robert Malster introduces his book 'North Sea War 1914-1919'. When thinking of the First World War at sea, many think only of the battle of Jutland. But across the North Sea there was constant naval activity throughout the conflict, activity often involving the small vessels of the Harwich Force, the submarines of Great Yarmouth and Harwich, the fishing vessels of Lowestoft and the naval aircraft of Felixstowe.
