The United Kingdom of Great Britain and Northern Ireland,commonly known as the United Kingdom (UK) and Britain, is a sovereign state located off the north-western coast of continental Europe. The country includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another state—the Republic of Ireland.Apart from this land border, the UK is surrounded by the Atlantic Ocean in the west and north, the North Sea in the east, the English Channel in the south and the IThe form of government is a constitutional monarchy with a parliamentary system. The capital city is London. The UK consists of four constituent countries:England, Scotland, Wales and Northern Ireland. The latter three have devolved administrations, each with varying powers, based in their capital cities,Edinburgh, Cardiff and Belfast 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 late 19th and early 20th centuries, 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 prevalence of language, culture and legal systems in many of its former colonies.

The UK is a developed country and has the world's sixth-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 powerand retains considerable economic, cultural, military, scientific and political influence internationally. It is a recognised nuclear weapons state and itsmilitary expenditure ranks fourth in the world.rish Sea in the west.Major sports, including association football, rugby league, rugby union, rowing, boxing, badminton, cricket, tennis, darts and golf, originated or were substantially developed in the United Kingdom and the states that preceded it. In most international competitions, separate teams represent England, Scotland and Wales. Northern Ireland and the Republic of Ireland usually field a single team representing all of Ireland, with notable exceptions being association football and theCommonwealth Games. In sporting contexts, the English, Scottish, Welsh and Northern Irish teams are often referred to collectively as the Home Nations. There are some sports in which a single team represents the whole of United Kingdom, including the Olympics, where the UK is represented by the Great Britain team. The 1908, 1948 Olympic Games and 2012 were held in London, making it the first city to play host for a third time.