Admiralty Pier Turret The Admiralty Pier Turret or Dover Turret , is an enclosed armoured turret built in 1882 on the western breakwater of Dover Harbour in southeast England . It contains two Fraser RML 16 inch 80 ton gun s , the biggest installed in the United Kingdom . Declared obsolete in 1902 , it is currently part of the port and inaccessible , though the guns remain in place . Admiralty Pier Fort . Admiralty Pier Fort , as distinct from Dover Turret , was commenced in 1872 as small fort at the extremity of Dover pier by adding a further extension and widening the pier for that purpose . In January 1872 Edward Druce , the engineer in charge , reported that the “ diving bells have commenced preparing the foundations of the fort ” and in January 1874 Druce reported that the substructure of the fort had been completed at a cost of £19 , 718 : 4 : 0 . The armament of the Admiralty Pier Fort was to be two 12 - inch muzzle - loading rifled guns of 25 tons as these guns were the most powerful available at the time . Dover Turret . In 1877 the Defence Committee noted that more powerful guns of 80 tons had been developed and they recommended that a turret be fitted on the Admiralty Pier Fort for two 80 - ton guns . The Superintendent of the Royal Gun Factory had been asked for designs for a powerful gun for capable of penetrating 20 inches of iron at a range of 1 , 000 yards and it was these guns that were eventually used as armament for the turret on the Admiralty Pier Fort . The gun took 18 months to build and by September 1875 the first gun was ready . Following test firings at the Royal Arsenal the gun was hauled onto the barge " Magog " and taken to Shoeburyness . By 1881 Admiralty Pier Fort was mostly complete and ready to receive its guns . The turret to hold the guns was constructed by the Thames Ironworks and Shipbuilding Company of Blackwall . This turret had a frame of wrought iron clad with three layers of 7 - inch armour with 2 - inch layers of iron and wood between them . Its weight including the two guns was 895 tons and it revolved on 32 rollers . The Thames Ironworks also built the machinery for the turret . There were four steam engines : The loading engine for loading running back and raising the ammunition , the main engine for rotating the turret , the auxiliary engine to replace either of the first two and the donkey engine which supplied water to the two boilers . In 1881 the Dover Telegraph reported on the proof trials of the turret ’ s No . 2 gun . At first it was proposed to move the guns to Dover by rail but this was considered to be too costly as a special carriage would be needed that would be useless for anything else . Eventually it was decided to move the guns by barge and use special sheers and holdfasts as anchors . The guns were lifted by manpower with a capstan instead of by machinery , permission being granted for this by the Board of Trade on condition that it all be removed as soon as possible after the guns were landed . An overhead traveller was constructed to move the guns across to the top of the turret and then lower them onto their carriages . The sheers weighed 100 tons and the traveller weighed 22 tons . They were tested in 1881 and the No . 1 gun arrived on 4 December 1881 . It was in place by 6 January 1882 . The No . 2 gun followed on 12 May 1882 . The turret machinery was ready for testing at the beginning of 1883 and the testing was arranged for July . The first shot was fired using a 250 pound charge . A second shot followed using a 337 pound charge and finally three shots were fired using a full battering charge of four hundred and fifty pounds of powder . The cliffs did not fall down as predicted , and neither did the fort itself but a couple of panes of glass were broken in the nearby lighthouse . By 1884 more experiments at Dover Turret had taken place with the electric lighting of the turret and the firing gear of the two guns . In 1885 the pier - head had been extended to landward and within this a new shell store , a coal bunker and a new cartridge store were built . In 1886 the committee assembled at the turret to watch the guns being fired . Four rounds were fired and the committee reported that the turret was ready to be handed over to the Royal Artillery . In 1887 a consultative committee decided that the efficiency of the two 80 - ton guns in the Dover Turret was diminished by the exposed position of the magazine . it was proposed to make a new shell store below the water line and to increase the thickness of the foundation of the turret with a mass of concrete . In 1891 the Dover Harbour Board wished to extend the pier - head to the seaward and to give it a more rounded shape due to the rip tide wearing it away . In 1893 the committee reported that the works for strengthening the magazines of Admiralty Pier Fort were nearing completion . Pier Turret Battery . A report of May 1886 stated that the Admiralty Pier had no defences of its own . Two 6 - inch B . L . guns were added on top of Admiralty Pier Fort either side of the turret by April 1909 . This was named as ‘ Pier Turret Battery ’ . The shell stores beneath the old turret were used to store ammunition for the new battery with shell lifts driven through the roof to each gun . Searchlights were added on the parapet of the pier . By this time the pier had been widened to allow construction of the pier extension . The guns installed in the battery were BL 6 - inch Mk VII s , one from Woolwich and one from South Front Battery . It was handed over to the Royal Artillery on 23 June 1909 . A battery command post was added on top of the old lighthouse which was no longer used as a new one had been built at the end of the Admiralty Pier extension . The later years . Between the two World Wars the Admiralty Pier Fort was transformed into a home for the battery Caretaker , who lived there with his wife and family . The guns remained in place inside the turret . In 1920 the Pier Turret Battery was reduced to " care and maintenance " but was used for drill by the Territorial Army . In April 1944 the battery became Home Guard Battery . According to the Fort record book the guns were withdrawn to Woolwich in August 1947 . In 1958 all of the battery buildings at Admiralty Pier Fort were demolished and the two BL 6 - inch emplacements tidied . One became a shelter and the other a small viewing platform . The fort itself and the turret remained . After a severe storm in 1987 the walkway along the pier was closed and the turret became inaccessible to the public . Most of the machinery inside the turret has been removed but the guns and their carriages remain together with parts of the shell lifts for the BL 6 - inch guns above . The turret remains under the control of Dover Harbour Board and there are no plans to restore it or open it to view . Originally situated at the end of the western breakwater , the main turret is now part way along , after the breakwater was extended in 1897 . It can be viewed from the adjacent Prince of Wales pier for free in daylight hours .