The United Kingdom of Great Britain and Northern Ireland (also known as the United Kingdom or Britain ) is a sovereign country located off the northwest coast of the continent of Europe . The United Kingdom consists of the archipelago of Great Britain and the northern part of the island of Ireland and many small islands. Northern Ireland is the only part of the kingdom with land borders that separates it from the Republic of Ireland . Other than that it borders the United Kingdom with the Atlantic Ocean, the North Sea, the English Channel and the so-called Irish Sea . The Channel Tunnel links Great Britain with France .
The United Kingdom is a country with a constitutional monarchy . It is a federal state according to a resolution in the year 1800 consisting of four regions: England , Northern Ireland, Scotland and Wales . governed by a parliamentary system and the government is concentrated in the capital , London , but there are local governments in Belfast, Cardiff, and Edinburgh, which are the capitals of Northern Ireland, Wales , and Scotland . The Bailiwick Jersey, the island of Guernsey, the Isle of Man and other islands belonging to the sovereignty of the United Kingdom , which means that they are constitutionally linked to the Kingdom but not part of it. The United Kingdom is governed by fourteen Territories called British Overseas Territories which are not a constitutional part of the United Kingdom and have absolute self-rule and conduct of their own affairs but their defense affairs belong to the United Kingdom. These lands are a relic of the British Empirewhich was at its height in 1922 and included almost a quarter of the land area in the world and the largest empire in history . British influence in language, culture, and legal systems is still noticed in many of its former colonies.
The UK is one of the developed countries , with its sixth economy globally in terms of gross domestic product and the sixth in terms of purchasing power parity. It was also the first country in the world to transform the industrial field was considered the largest superpower in the world during the nineteenth and early twentieth centuries . However, with the economic and social costs of two world wars, the empire retreated in the latter half of the twentieth century, leading to a diminished leadership role in world affairs. The United Kingdom remains, however, a strong power with strong economic, cultural, military, scientific and political influence. It is also a nuclear country and has the third or fourth highest military spending in the world according to the method of calculating expenditures in 2008. United Kingdom is a member of the European Union but voted to secede from it on June 22, 2016 and is also a permanent member of the Security Council as well as a member of The Commonwealth is a member of the Group of Eight and the Group of Twenty and the North Atlantic Treaty Organization and a member of the Organization for Economic Cooperation and Development and the World Trade Organization .