Today's state is the latest of several unions formed over the last 1000 years. Scotland and England have existed as separate unified entities since the 10th century. Wales, under English control since the Statute of Rhuddlan in 1284, became part of the Kingdom of England by the Laws in Wales Act 1535. With the Act of Union 1707, the separate kingdoms of England and Scotland, having shared the same monarch since 1603, agreed to a permanent union as the Kingdom of Great Britain.

Parliamentary Union of England and Scotland 1707,
painting by Walter Thomas Monnington.

The Act of Union 1800 united the Kingdom of Great Britain with the Kingdom of Ireland, which had been gradually brought under English control between 1169 and 1691, to form the United Kingdom of Great Britain and Ireland.

The United Kingdom of Great Britain and Northern Ireland was formed in 1922, after bitter fighting which echoes down to the current political strife, the Anglo-Irish Treaty partitioned Ireland into the Irish Free State and Northern Ireland, with the latter remaining part of the United Kingdom. As provided for in the treaty, Northern Ireland, which consists of six of the nine counties of the Irish province of Ulster, immediately opted out of the Free State and to remain in the UK. The nomenclature of the UK was changed in 1927 to recognise the departure of most of Ireland, with the current name being adopted.

The British Empire in 1897.

The United Kingdom, the dominant industrial and maritime power of the 19th century, played a leading role in developing Western world ideas of property, liberty, capitalism and parliamentary democracy - to say nothing of its part in advancing world literature and science. At its zenith, the British Empire stretched over one quarter of the Earth's surface and encompassed a third of its population. The first half of the 20th century saw the UK's strength seriously depleted from the effects of World War I and World War II. The second half witnessed the dismantling of the Empire and the UK rebuilding itself into a modern and prosperous nation.

The UK has been a member of the European Union since 1973. Its attitude towards further integration is conservative, and there is significant Euroscepticism in UK politics. It has not chosen to adopt the Euro, owing to internal political considerations and the government's judgement of the prevailing economic conditions.