The United Kingdom (in English: United Kingdom), note 1 officially called United Kingdom of Great Britain and Northern Ireland (United Kingdom of Great Britain and Northern Ireland), 5 is a sovereign and insular country, member of the European Union, located northwest of Continental Europe. Its territory is formed geographically by the island of Great Britain, the northeast of the island of Ireland and small adjacent islands. Northern Ireland is the only part of the country with a land border, which separates it from the Republic of Ireland. Great Britain bounded on the north and west by the Atlantic Ocean, on the east by the North Sea, on the south by the English Channel and on the west by the Irish Sea.

The United Kingdom is a unitary State comprised of four constituent nations: Scotland, Wales, England and Northern Ireland.6 It is governed by a parliamentary system with headquarters and capital in London, but with three decentralized national administrations in Edinburgh, Cardiff and Belfast, the capitals of Scotland, Wales and Northern Ireland, respectively. It is a parliamentary monarchy being Isabel II the head of state. Colloquially and erroneously is denominated Great Britain and England, consequence of the greater weight of both (territory and kingdom respectively) within the State. The Crown Dependencies of the Channel Islands and the Isle of Man are not part of the country, but they are integrated into a personal union with it.7

The United Kingdom has fourteen overseas territories, all vestiges of what was the British Empire, which in its international territory came to reach and cover, about a quarter of the world's land area. Isabel II continues to be at the head of the Commonwealth of Nations and as head of State of each of the Kingdoms of the Commonwealth.