The population of the United Kingdom was estimated at over 67.0 million in 2020. It is the 21st most populated country in the world and has a population density of 270 people per square kilometre (700 people/sq mi), with England having significantly greater density than Wales, Scotland, and Northern Ireland. 
The history of the United Kingdom began in the early eighteenth century with the Treaty of Union and Acts of Union. The core of the United Kingdom as a unified state came into being in 1707 with the political union of the kingdoms of England and Scotland, into a new unitary state called Great Britain.
The monarchy of the United Kingdom, commonly referred to as the British monarchy, is the constitutional form of government by which a hereditary sovereign reigns as the head of state of the United Kingdom, the Crown Dependencies and the British Overseas Territories.
t. e. His Majesty's Government (or, when the reigning monarch is female, Her Majesty's Government; abbreviated to HM Government, and commonly known as the Government of the United Kingdom, British Government or UK Government) is the central executive authority of the United Kingdom of Great Britain and Northern Ireland.
The United Kingdom Portal. 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 north-western coast of the continental mainland. It comprises England, Scotland, Wales, and Northern Ireland.
2 days ago · United Kingdom, island country located off the northwestern coast of mainland Europe. It comprises the whole of the island of Great Britain—which contains England, Wales, and Scotland—as well as the northern portion of the island of Ireland. Its capital is London.
United Kingdom; British Empire; History of Europe; History of England; Footnotes. ¹ The term "United Kingdom" was first used in the Union with Scotland Act 1706. However it is generally seen as a descriptive term, indicating that the kingdoms were freely united rather than through conquest.