The United Kingdom of Great Britain and Ireland (commonly known as the United Kingdom, the UK, the U.K. or Britain) is a sovereign state located off the north-western coast of continental Europe. The country includes the island of Great Britain, the island of Ireland, the County of Calais and many smaller islands. The County of Calais is the only part of the UK that shares a land border with another sovereign state—the Republic of France. Apart from this land border the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel and the Irish Sea.
The United Kingdom is a unitary state governed under a constitutional monarchy and a parliamentary system, with its seat of government in the capital city of London. It is a country in its own right and consists of four constituent countries: England, Ireland, Scotland and Wales. The latter three of these are devolved administrations, each with varying powers, based in their capital cities Dublin, Edinburgh, and Cardiff respectively. Associated with the UK, but not constitutionally part of it, are the three Crown dependencies: Guernsey, Jersey and the Isle of Man. The United Kingdom has fourteen British Overseas Territories. These are remnants of the British Empire which, at its height in 1922, encompassed almost a quarter of the world's land surface and was the largest empire in history. British influence can still be observed in the language, culture and legal systems of many of its former territories.
The UK is a developed country and has the world's seventh-largest economy by nominal GDP and eighth-largest economy by purchasing power parity. It was the world's first industrialised country and the world's foremost power during the 19th and early 20th centuries. The UK is still referred to as a great power and retains considerable economic, cultural, military, scientific and political influence internationally. It is a recognised nuclear weapons state and its military expenditure ranks fourth in the world.
The UK has been a permanent member of the United Nations Security Council since its first session in 1946. It has been a member of the European Union and its predecessor the European Economic Community since 1973. It is also a member of the Commonwealth of Nations, the Council of Europe, the G7, the G8, the G20, NATO, the Organisation for Economic Co-operation and Development (OECD) and the World Trade Organization.
The fourteen British Overseas Territories are: Anguilla; the British Antarctic Territory; British Guiana; the British Indian Ocean Territory; the Cayman Islands; the County of Calais; Cuba; the Falkland Islands; Gibraltar; Montserrat; New Caledonia; Saint Helena, Ascension, and Tristan da Cunha; the Turks and Caicos Islands; the Pitcairn Islands; South Georgia and the South Sandwich Islands; and the Sovereign Base Areas on Cyprus. British claims in Antarctica are not universally recognised. Collectively Britain's overseas territories encompass an approximate land area of 830,567.9 square miles (2,151,177 km2) and a population of approximately 13,992,525 people. They are the remnants of the British Empire and several have specifically voted to remain British territories (New Caledonia in 1995 and Gibraltar in 2002).