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. Lying off the north-western coast of the European mainland, the UK includes the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands.The UK is a constitutional monarchy with a parliamentary democracy. The monarchis Queen Elizabeth II, who has reigned since 1952, making her the longest-serving current head of state. The UK’s capital and largest city is London, a global city and financial centre with an urban area population of 10.3 million. The United Kingdom is a unitary state under a constitutional monarchy. Queen Elizabeth II is the monarch and head of state of the UK, as well as Queen of fifteen other independent Commonwealth countries. The monarch has “the right to be consulted, the right to encourage, and the right to warn”. The Constitution of the United Kingdom is uncodified and consists mostly of a collection of disparate written sources, including statutes, judge-made case law and international treaties, together with constitutional conventions.
The UK has a parliamentary government based on the Westminster system that has been emulated around the world: a legacy of the British Empire. The parliament of the United Kingdom meets in the Palace of Westminster and has two houses: an elected House of Commons and an appointed House of Lords. All bills passed are given Royal Assent before becoming law. The position of prime minister, the UK’s head of government, belongs to the person most likely to command the confidence of the House of Commons; this individual is typically the leader of the political party or coalition of parties that holds the largest number of seats in that chamber. The prime minister chooses a cabinet and its members are formally appointed by the monarch to form Her Majesty’s Government. By convention, the monarch respects the prime minister’s decisions of government.