The United Kingdom of Great Britain and Northern Ireland is the sovereign state Great Britain, i.e., England, Scotland and Wales, and Northern Ireland. Since 9th century, England and Scotland existed as separate sovereign and independent states with their own monarchs and political structures.

The once independent Principality of Wales fell under the control of English monarchs from the Statute of Rhuddlan in 1284. Although, England (including Wales) and Scotland had been in personal union since the Union of the Crowns in 1603, agreed to a political union in the form of a unified Kingdom of Great Britain under the Acts of Union 1707.

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 1541 and 1691, to form the United Kingdom of Great Britain and Ireland in 1801. With the formation of 26 Irish counties, the Irish declared independence in 1922 and the Republic of Ireland was born. However, six of the nine counties of the province of Ulster decided to remain within the UK. Thus the earlier name was changed to the current one in 1927, the United Kingdom of Great Britain and Northern Ireland.

Britain played a significant role during the Age of Enlightenment with philosophical and scientific input and a literary and theatrical tradition. Over the next century, the United Kingdom developed Western ideas of parliamentary democracy contributing considerably to literature, arts and science. The Industrial Revolution transformed the UK that eventually led to the formation of the British Empire. During this time, the United Kingdom was involved in colonial exploitation including the slave trade. Nonetheless, the passing of the 1807 Slave Trade Act made the UK the first country to prohibit slave trade.

Britain emerged as the principal naval power of the 19th century after the defeat of Napoleon in the Napoleonic Wars. During this time, the British Empire had control of huge amounts of territory in Asia, Africa, Oceania and America. During this period, the UK played a vital part in the development of parliamentary democracy, partly through the emergence of a multi-party system.

Towards the Victorian era, the United Kingdom lost its industrial leadership to the German Empire in particular and the United States. However, Britain remained an eminent power and its empire expanded to its maximum size by 1921, gaining the League of Nations mandate over former German and Ottoman colonies after World War I.

The United Kingdom was the only Allied European country to remain free from occupation during World War II. In 1924, the country's Labor movement that had been gaining strength since the late 1890s formed the first Labor government. Britain fought Nazi Germany in World War II, with its Commonwealth allies including Canada, Australia, New Zealand, South Africa and India, who were later joined by further allies such as the United States.

The end of the World War II saw a massive win for Clement Atlee and the Labor Party in the General Election. They were elected on a manifesto of social justice and left wing policies such as the creation of a National Health Service and the provision of council housing. This was also the time when the UK was poor, relying heavily on loans from the United States of America to rebuild its damaged infrastructure. Rationing and conscription dragged on into the post war years and the country suffered one of the worst winters on record.

The 1950’s brought in several transformations in the United Kingdom for good. The rebuilding of the nation continued and several immigrants from the remaining British Empire were invited to help the rebuilding effort. Towards the end of 1950’s, the UK had lost its place as a superpower and resulted in decolonization and withdrawal from almost all of its colonies by 1970. The 1950’s and 1960’s were relatively prosperous times after the World War II. This period saw the beginning of a modernization of the UK with the construction of its first motorways.

The 1970’s and 1980’s saw the integration of the United Kingdom into the European Economic Community and a strict modernization of its economy. It was, however, the time of high unemployment as result of de-industrialization. After the difficult periods in 1970’s and 1980s, 1990s saw the beginning of a period of continuous economic growth that has to date lasted over 15 years.