United Kingdom

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign country in -western Europe, off the -­western coast of the European mainland.

The United Kingdom includes the island of Great Britain, the -­eastern part of the island of Ireland, and many smaller islands within the  Isles.

Northern Ireland shares a land border with the Republic of Ireland. Otherwise, the United Kingdom is surrounded by the Atlantic , with the   to the , the  Channel to the and the Celtic  to the -, giving it the 12th-longest coastline in the world.

The Irish  separates Great Britain and Ireland. The total area of the United Kingdom is 93,628 square miles (242,500 km2).

The United Kingdom is a unitary parliamentary democracy and constitutional monarchy.

The monarch, Queen Elizabeth II, has reigned since 1952. The and largest  is London, a global and financial center with an urban area population of 10.3 million.

The United Kingdom consists of four countries: EnglandScotland, Wales and Northern Ireland. Other than , the constituent countries have their own devolved governments, each with varying powers.

The United Kingdom has evolved from a of annexations, unions and separations of constituent countries over several hundred years.

The Treaty of Union between the Kingdom of  (which included Wales, annexed in 1542) and the Kingdom of Scotland in 1707 formed the Kingdom of Great Britain.

Its union in 1801 with the Kingdom of Ireland created the United Kingdom of Great Britain and Ireland.

Most of Ireland seceded from the UK in 1922, leaving the present United Kingdom of Great Britain and Northern Ireland, which formally adopted that name in 1927.

The nearby Isle of Man, Guernsey and Jersey are not part of the UK, being Crown Dependencies with the   responsible for defence and international representation.

There are also 14  Overseas Territories, the last remnants of the  Empire which, at its height in the 1920s, encompassed almost a quarter of the world’s landmass and a third of the world’s population, and was the largest empire in .

influence can be observed in the language, culture and the legal and political systems of many of its former colonies.

The United Kingdom has the world’s fifth-largest economy by nominal gross domestic product (GDP), and the tenth-largest by purchasing power parity (PPP). It has a high-income economy and a very high  development index rating, ranking 13th in the world.

The UK became the world’s first industrialised country and was the world’s foremost power during the 19th and early 20th centuries.

Today the UK remains one of the world’s great powers, with considerable economic, cultural, military, scientific, technological and political influence internationally.

It is a recognized nuclear  and is ranked fourth globally in military expenditure.

It has been a permanent member of the United Nations Security Council since its first session in 1946.

The United Kingdom is a member of the Commonwealth of Nations, the Council of Europe, the G7, the Group of Ten, the G20, the United Nations, NATO, AUKUS, the Organisation for Economic Co-operation and Development (OECD), Interpol, and the World Trade Organization (WTO).

It was a member of the European Communities (EC) and its successor, the European Union (EU), from its accession in 1973 until its withdrawal in 2020 following a referendum held in 2016.