In 1922, five-sixths of Ireland seceded from the UK, leaving the present formulation of the United Kingdom of Great Britain and Northern Ireland.
The capital of the UK and its largest city is London, a global city and financial centre with an urban area population of 10.3 million, the fourth-largest in Europe and second-largest in the European Union.
based in their capitals, Edinburgh, Cardiff and Belfast, respectively.
Although the United Kingdom, as a sovereign state, is a country, England, Scotland, Wales, and to a lesser degree, Northern Ireland, are also regarded as countries, though they are not sovereign states.
The term Britain is often used as synonym for the United Kingdom.
Wales was annexed by the Kingdom of England under the Laws in Wales Acts 15.
A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands.Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world.The UK is considered to have a high-income economy and is categorised as very high in the Human Development Index, ranking 14th in the world.It was the world's first industrialised country and the world's foremost power during the 19th and early 20th centuries.The Irish Sea lies between Great Britain and Ireland.