The Southern Breakwater was begun in 1898 and completed by 1909 as part of the Admiralty Harbour, which also included the Eastern Arm and an extension to the Admiralty Pier. In an era of torpedo assaults this harbour was designed to provide a protected anchorage for the naval fleet and increase the protection of the already existing commercial harbour. Admiralty Harbour was constructed by the firm of Coode, Son and Mathews, the successor firm to Sir John Coode, probably the greatest harbour engineer of the C19. Each of the three component parts of the Harbour had defences; the Southern Breakwater receiving two six-inch guns installed in concrete emplacements with associated accommodation and magazines. The defences were installed to the far west end of the breakwater, and became known as the Breakwater Battery.

During the First World War the Harbour protected the Dover Patrol, a fleet of about 40 warships, motor boats and fishing vessels which kept control of the English Channel. Following the end of the War, in 1926, it was decided that the harbour had limited military use and the three component structures were handed over to the Dover Harbour Board for administration as a commercial undertaking. With the outbreak of the Second World War, however, the harbour once again became a naval base. The breakwater batteries were reinforced, the Southern Breakwater receiving a new twin six-pounder battery in May 1940. The 'Knuckle', as the curved east end of the Southern Breakwater was known, was equipped with searchlight emplacements and towards the end of the war two four-inch guns were added. During the Second World War, the harbour was particularly important in the 1940 Dunkirk evacuation as 200,000 men were returned from Dunkirk to Dover in eight days. After 1945, the Navy withdrew and the harbour was once again returned to commercial activity. (1-3)

<1> Victor Smith and Andrew Saunders, 2001, Kent's Defence Heritage, KD107 (Unpublished document). SKE6956.

<2> English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.

<3> C. Dobson, 2000, Twentieth century fortifications in England: Coast Artillery 1900-1956 (Monograph). SKE52187.