During the Second World War, the British government built a fort (Roughs Tower) on the High Seas 11 km (7 miles) off the east coast of the United Kingdom, which was a base for radar, heavy armament and about 200 service personnel, to guard and protect the approaches to the Thames Estuary. Essentially it is a landing platform measuring 1,300 m² (13,990 ft), connected to the sea-bed by concrete pillars. Following the war, the island remained derelict until 1966, when a British family took possession and declared the Principality (or Duchy) of Sealand and spent many years struggling to have their claim recognised, arguing that most major European states and international lawyers have declared that Sealand fulfilled all the legal requirements for a state, and that the sovereignty of Sealand was absolute and unquestionable. The occupiers produced their own constitution, flag, national anthem, currency – the Sealand dollar - and passports (by 1975, 106 persons possessed 'citizenship of Sealand'). It was put up for sale in 2007 and this has now raised again the question of the legal status of the Principality.It has declared itself a tax free zone and there are no gaming restrictions of customs duties.Pic: Alamy