The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of the continental mainland. It comprises the countries of England, Scotland, Wales, and Northern Ireland. The UK includes the island of Great Britain, the north-eastern part of the island of Ireland, and most of the smaller islands within the British Isles, a total area of 94,354 square miles (244,376 km2). Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea, and the Irish Sea. The United Kingdom had an estimated population of nearly 68.3 million people in 2023. The capital and largest city of both England and the United Kingdom is London, whose wider metropolitan area is the largest in Western Europe, with a population of 14.9 million. The cities of Edinburgh, Cardiff, and Belfast are the national capitals of Scotland, Wales, and Northern Ireland, respectively.The lands of the UK have been inhabited continuously since the Neolithic. In AD 43 the Roman conquest of Britain began; the Roman departure was followed by Anglo-Saxon settlement. In 1066, the Normans conquered England. With the end of the Wars of the Roses the English state stabilised and began to grow in power, resulting by the 16th century in the annexation of Wales, the domination of Scotland, and the establishment of the British Empire. Over the course of the 17th century, the role of the British monarchy was reduced, particularly as a result of the English Civil War. In 1707, the Kingdom of England and the Kingdom of Scotland united under the Treaty of Union to create the Kingdom of Great Britain. The Acts of Union 1800 incorporated the Kingdom of Ireland to create the United Kingdom of Great Britain and Ireland in 1801. Most of Ireland seceded from the UK in 1922 as the Irish Free State, and the Royal and Parliamentary Titles Act 1927 created the present United Kingdom.
The UK became the first industrialised country and was the world's foremost power for the majority of the 19th and early 20th centuries, particularly during the "Pax Britannica" between 1815 and 1914. At its height in the 1920s, the British Empire encompassed almost a quarter of the world's landmass and population, and was the largest empire in history. However, its involvement in the First World War and the Second World War damaged Britain's economic power and a global wave of
decolonisation led to the independence of most British colonies.
The United Kingdom is a constitutional monarchy and parliamentary democracy. The UK has three distinct jurisdictions: England and Wales, Scotland, and Northern Ireland. Since 1999, Scotland, Wales and Northern Ireland have their own governments and parliaments which control various devolved matters. A developed country, the UK has the world's sixth-largest economy by nominal gross domestic product (GDP). It is a nuclear state, and is ranked fifth globally in military expenditure. The UK has been a permanent member of the UN Security Council since its first session in 1946. It is a member of the Commonwealth of Nations, Council of Europe, G7, OECD, NATO, Five Eyes, AUKUS and CPTPP. British influence can be observed in the legal and political systems of many of its former colonies, and British culture remains globally influential, particularly in language, literature, music and sport. English is the world's most widely spoken language and the third-most spoken native language.
The culture of the United Kingdom is influenced by many factors including: the nation's island status; its history; and being a political union of four countries with each preserving elements of distinctive traditions, customs and symbolism. As a result of the British Empire, British influence can be observed in the language, culture and legal systems of many of its former colonies, in particular, the United States, Australia, Canada, New Zealand, and Ireland, a common culture known today as the Anglosphere. The substantial cultural influence of the United Kingdom has led to it being described as a cultural superpower. A global survey in 2023 ranked the UK 3rd in the 'Most Influential Countries' rankings (behind the US and China).
The English playwright and poet William Shakespeare is widely regarded as the greatest dramatist of all time. Other important English writers include Geoffrey Chaucer, known for The Canterbury Tales, the poet William Wordsworth and other romantic poets, also the novelists Charles Dickens, H. G. Wells, George Orwell and Ian Fleming. The 20th-century English crime writer Agatha Christie is the best-selling novelist of all time. Twelve of the top 25 of 100 novels by British writers chosen by a BBC poll of global critics were written by women; these included works by George Eliot, Virginia Woolf, Charlotte and Emily Brontë, Mary Shelley, Jane Austen, Doris Lessing and Zadie Smith.
