Coastal fortifications of Jersey Jersey is a heavily fortified island with coastal fortification s that date from different periods such as the English Civil War , the Napoleonic Wars , and Nazi Germany ' s occupation of the Channel Islands . The fortifications include castle s , fort s , towers , Martello tower s , artillery batteries , and seawall s . Not infrequently , fortifications from one period are built on the site of earlier fortifications , or very near them , geography having remained the same even when firepower increased . As of 2013 , some of the fortifications are museums , or holiday accommodation , private homes , and event and sport venues . Most are under the control of the States of Jersey , Jersey Heritage , the National Trust for Jersey , and the Channel Islands Occupation Society . Coastal towers ( pre - World War II ) . Coastal towers stand all along the coast of the island . The British built 22 round towers , one similar square tower , and eight Martello tower s towards the end of the 18th Century and in the early to mid - 19th Century , but now only 24 remain , including seven of the Martellos . Conway ' s towers . On 28 May 1778 the Governor of Jersey , Field Marshal Henry Seymour Conway , submitted plans to Lord Weymouth for the construction of 30 coastal towers to forestall , or at least impede French incursions on the island . King George III granted approval and funding on 5 July 1778 . Work began in 1779 , after a failed French landing at St Ouen ' s Bay on 1 May 1779 . Perhaps four had been completed by the time of the Battle of Jersey in 1781 , in which however they played no part . Guernsey , which the French did not attack , had built 15 loophole towers between 1778 and 1779 . Seymour Tower , which replaced an earlier tower on the same spot at La Rocque , was built of granite and was the only square tower . The other 22 towers that Conway had constructed were round . Although frequently called Martello tower s , the round towers are taller , and they predate the development of true Martello towers . The round towers differ from Martello towers in several ways . The Jersey towers are mostly built with local granite rather than brick , have a slighter batter ( taper ) , and most importantly , originally did not have a cannon on the top platform . ( The Guernsey round towers have a strong batter on the ground floor and no machicolation s ; they too initially did not carry a gun on the top platform . ) Later , at the onset of the Napoleonic Wars , both the Jersey and Guernsey towers each received a 12 - pounder carronade on a pivot mount for the top platform . During the German occupation of the Channel Islands during World War II , the Germans adapted some of the towers to their own purposes . The Germans also destroyed several towers . Some of the surviving towers have been painted on the seaward side to serve as daymark s ( navigational aids ) . Archirondel is painted red and white , while other towers are painted white and red , or white , in whole or in part , again , on the seaward side . The order below is counter - clockwise from the north - west corner of the island . The latest Jersey pound note design ( 2010 ) has a picture of the St Clement ' s tower at Le Hocq . This tower also appears on the reverse of the Jersey 1p coin . Martello towers . The British built eight true Martello towers in Jersey , three between 1808 and 1814 , and five between 1834 and 1837 . The German occupation forces destroyed one of the second group , L ' Etacq , during World War II . World War II coastal fortifications . During World War II Nazi Germany constructed a considerable number of fortifications in the Channel Islands which form part of the Atlantic Wall . The Channel Islands were amongst the most heavily fortified parts of the Atlantic Wall , particularly Alderney which is the closest to France . In Jersey , the fortifications include Hohlgangsanlage tunnels and artillery batteries such as Battery Moltke and Battery Lothringen . The most distinctive new structures the Germans built were the Marine Peilstand ( MP ) towers that they used to search for targets at sea . The Germans had intended to build nine towers , but only completed three . These towers are round and have five or more floors with observation embrasures , as well as defensive embrasures . MP1 is part of Battery Lothringen , MP2 overlooks Corbière lighthouse and is now known as the Radio Tower , and MP3 is part of Battery Moltke . The design of the towers inadvertently and somewhat ironically reflect the Bauhaus movement of Modernist architecture ( 1919 - 1933 ) , a movement that the Nazis had tried to suppress . As well as building many new fortifications , the German forces made their own additions to some of the existing fortifications . These additions include gun emplacements and various types of bunkers . Organisation Todt built the fortifications using imported labour , primarily prisoners of war and workers deported from occupied countries . The Germans transported over 16 , 000 slave workers to the Channel Islands to build the fortifications .