As so many merchant ships were sunk during the First World War, in 1917 the government decided to establish a number of national shipyards. In accordance with the Protection of the Realm Act, all Chepstow shipbuilding companies came under government control. They were expanded to form National Shipyard Number 1 (Chepstow). Over 6,000 men from the Royal Engineers built the shipyard, and men from Tyneside and the Clyde came to work at the yard. Garden cities were built for the workers in Hardwick, Bulwark and Pennsylvania. The concrete blocks used to construct the houses were produced by German prisoners of war. Camps were built for the workers, along with workshops, a power station and hospital. In 1925 Fairfield Shipbuilding and Engineering Ltd bought and later dismantled the shipyard. In due course the company became Fairfield-Mabey Ltd who now specialise in steelwork for bridges and other structures.

References: Gwent Record Office: Administrative History for the records of Messrs Fairfield-Mabey Ltd, Structural Engineers, Chepstow; Gathering the Jewels, description for items from the shipyard in Chepstow Museum.