The United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the north-western coast of continental Europe. The United Kingdom comprises four countries: England, Northern Ireland, Scotland and Wales; and fourteen overseas territories. 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 Irish Sea in the west.

It was the world's first industrialized country and the world's foremost power during the 19th and early 20th centuries. The UK remains a great power with considerable economic, cultural, military, scientific and political influence internationally.

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 (EEC) since 1973; it is also a member of the Commonwealth of Nations, the Council of Europe, the G7, the G8, the G20, NATO, the Organization for Economic Co-operation and Development and the World Trade Organization.