The Kingdom of Great Britain, also known as the United Kingdom of Great Britain, was a state in Western Europe, in existence from 1707 to 1800. It was created by the merger of the Kingdom of Scotland and the Kingdom of England, under the Acts of Union 1707, to create a single kingdom encompassing the whole of the island of Great Britain. A new single parliament and government, based in Westminster in London, controlled the new kingdom. The two separate kingdoms of Scotland and England had shared the same monarch since James VI, King of Scots, became King of England in 1603 following the death of Queen Elizabeth I.
The Kingdom of Great Britain was superseded by the United Kingdom of Great Britain and Ireland in 1801 when the Kingdom of Ireland was absorbed with the enactment of the Act of Union 1800 following the suppression of the Irish Rebellion of 1798.

Political structure
Often, the Kingdom of Great Britain is given the alternative name of the United Kingdom of Great Britain, which is often shortened to United Kingdom. There is substantial debate over whether the latter name is acceptable.
The name "United Kingdom" is sometimes preferred for purposes of continuity, particularly in the military and colonial spheres. At the time of the Act of Union 1800, which unambiguously styled the country as the "United Kingdom", the British were embroiled in the Great French War and the British Empire possessed many colonies in the Americas, India, and Australia. Some who would otherwise prefer the term "Kingdom of Great Britain" thus use "United Kingdom" to avoid using two different names for a single military and colonial power, which may confuse the discussion.
However "United Kingdom" seems to have come into popular use, and so at the time of the Act of Union with Ireland the name was officially adopted.