Plans for a new National, or Admiralty Harbour were drawn up in September 1897. These plans proposed the extension of the existing Admiralty Pier and the building of a second pier (the Eastern Arm) of about the same length on the other side of the bay, a mile and a half away. The gap between the two piers was to be bridged by a detached Mole or Southern Breakwater, with an entrance to the harbour at each end of it. The contract for its construction was awarded to S. Pearson & Son in April 1898. This major building project took over ten years, the harbour finally being completed in 1909. At the outbreak of the First World War in August 1914 civilian cross Channel services were withdrawn. The Admiralty Harbour was used by the Dover Patrol throughout the war. In January 1919 an intermittent ferry service to Ostend started, with a daily service commencing in June when the minefields had been cleared. A service to Boulogne resumed later the same year, and to Calais in 1920. The Admiralty realised during the First World War that large naval vessels in Dover were very vulnerable to air attack. In 1919 the Admiralty decided to abandon Dover as a naval port, retaining only certain installations at the Camber by the Eastern Arm where old naval craft were broken up in the early 1920s. All other installations were handed over to the Harbour Board with the proviso that, should the need arise, the Admiralty could resume possession without having to pay any compensation for improvements that the Harbour Board may have made in the interim. The Navy returned in force at the outbreak of the Second WorldWar. The harbour was again closed to civilian traffic and played a major role in the evacuation of Dunkirk. The Admiralty returned control to the Harbour Board after the war never to return. The regular cross-Channel service to Calais resumed in April 1946, to Ostend in September the same year and the train ferry service to Dunkirk in December 1947. It is still the Admiralty Harbour that forms the framework of Dover Harbour as it is today.