Across the English Channel from France and the rest of continental Europe lies the United Kingdom of Great Britain and Northern Ireland (UK).  The UK comprises four parts: England , Scotland , Wales and  Northern Ireland.

Britain was not unknown to the great classical civilisations of Greece and Rome - the Greeks and Carthaginians traded with the Britons as early as the 4th century BC, although some regarded it as a mysterious island, and some refused to believe it existed.

From 55 BC, the British mainland was subjected to waves of invaders and settlers. The Romans first arrived in Britain when Julius Caesar, then a general in the Roman army, landed. He did not make much headway into Britain and soon left. However, some Celtic chieftains were now influenced by the Romans. It was not until AD 43 that Emperor Claudius ordered the invasion of Britain. The Romans were never able to conquer the whole island, reports that survive from this period show an army of men terrified at the sight of their multi-tattoed, scantily clad, and blue painted opponents.(for reference, read Caesar's Commentarii De Bello Gallico or the Annals of Tacitus.)   The Romans eventually built  Hadrian's Wall, a wall constructed along the line of the border between Roman Britain and the lands where the Picts, Scots and Gaels lived, still stands to this day in places, including the fort at Housesteads, which is a popular tourist site. Indeed, the wall is a UNESCO World Heritage site. Other Roman sites worthy of visiting in Britain are Caerleon, a Roman fort with amphitheatre and bath-house near Newport in South Wales, Fishbourne's Roman villa and the castle at Pevensey near Eastbourne. Cities that grew up on Roman settlements include Colchester (Camlulodunon, the first Roman "city"), London (Londinium), Gloucester (Glevum), Cirencester (Corinium), and Bath (Aquae Sulis). Many of these places contain Roman remains and exhibits.

With the decline of the Roman empire, Britain became what is known as Sub-Roman Britain, with a system of rule based upon the Roman system, until the Angles, Saxons and Jutes from northern Germany invaded the southern part of the mainland. 

From the 8th to the 10th centuries, the Vikings from Denmark and Norway first raided the east coast and then came en masse to settle. The eastern half of England and Scotland (both to become semi-Germanic countries), along with parts of Ireland, were heavily settled, though the Vikings tended to live alongside the Saxons, perhaps in a separate village further up the valley.  Danish kings ruled parts of England as well as the Scottish Isles and Dublin for a couple of centuries, and England was even briefly united with Denmark under one king - Cnut (also known as Canute) - in the 11th Century.

Out of the 'dark ages' emerged the geographical entities and culturally and politically separate nations of England, Scotland, Wales and Ireland.  Over the centuries, Scotland, England and the Welsh and Irish tribes would struggle to defend themselves against attempts at invasion and suppression by the other inhabitants of the British Isles. Wales would be overrun by the Plantagenets, later to become a principality of England. Ireland was conquered piecemeal by the then united Sots, Welsh and English, until during the early years of the 20th century the larger portion of the island gained independence from the rest of Britain. Not least due its larger population, England was the most powerful nation of not just Great Britain, but all of Britain, but in the 17th century the demise of the Tudor dynasty in England upon the death of Elizabeth Tudor led to the offer of the English crown to King James VI of Scotland (of the junior Stuart line), effecting a union of the crowns of Scotland and England.

James was crowned King James I of England & Lord of Ireland in 1603 (he often used the title King of Great Britain), marking the beginning of the entity known as the United Kingdom.  Both England & Scotland continued to have their own parliaments. Full political union of the United Kingdom under a single parliament would not take place until 1707, in which the Scottish and English parliaments were united, forming the modern Westminster parliament.

James's absolutist son, Charles I, attempted to impose the English prayer book on the Scottish Presbyterian Church. His policies angered the English Parliament enough that, in 1642, civil war broke out between King and Parliament, with the Scots participating on the Parliamentarian side. Parliament won the civil war, and for a brief period, England was ruled as a Commonweath by Oliver Cromwell as Lord Protector. With Cromwell's death came the restoration of the monarchy in a constitutional model, and greater colonial adventures overseas under Charles' son Charles II (The Merry Monarch). Scotland, under the Stuart descendants of "Jamie Saxt" (sixth), who was later described by the historian MacAuley as "the wisest fool in Christendom" was becoming overshadowed by the increasingly economically and militarily powerful England.

The new United Kingdom of Great Britain (Ireland would be added to the title in 1801) became, during the 18th century, a power-broker within Europe, usually siding with the weaker powers in a war in an attempt to maintain the balance of power and prevent any one power (particularly a Catholic one such as France) from gaining too much power.

Britain was also the cradle of the Industrial Revolution during the 18th century and a network of canals, factories and workshops sprang up all round the country.  This transformed the landscapes forever, particularly in the Midlands and Lancashire in England, and the Clyde Valley in Scotland.  It was the increased industrial might of Britain that led to eventual victory in the Napoleonic Wars, after which Britain withdrew from an active role in European politics contenting herself with the business of trading, becoming prosperous and - almost incidentally - acquiring a new empire to replace the American colonies lost in 1776. Ironically, the violent revolution of those American colonies caused a mass-migration of loyalists to other areas of the empire, mainly to the province of 'Upper Canada', providing a significant boost to that country; today their descendants are known by the term 'United Empire Loyalists'. India, for instance, became part of the British Empire almost by accident: trading posts set up by the East India Company were defended by East India Company soldiers, and gradually became more and more involved in local politics until Britain found herself ruling India by proxy.

Britain wasn't slow during the later 19th century to be a little more deliberate about her colonization, especially in Africa and South-East Asia. Australia, meanwhile, was transforming herself from a penal colony into a fully-fledged colony attracting willing immigrants.

In 1914, Britain found herself involved in a European war that became a World War. The trenches of Flanders - not to mention battles in Gallipoli, Mesopotamia, Italy and Salonika - consumed a generation of young men and left Britain economically shattered despite her victory.

The "Irish Question" which had poisoned British politics for a generation was also finally "settled" with the granting of independence to the Irish Republic in 1921.  However, the northern part of the island had been heavily colonised by Scots and Englishers during the 17th and 18th centuries, and the majority there were in favour of continued union with the rest of Britain. After independence, many of the loyalist inhabitants of southern Ireland also emigrated to the Unionist north, thus forming the strongly patriotic, monarchist, pro-Union culture evident today. Thus six original counties of Ireland split from the rest and the country became the United Kingdom of Great Britain and Northern Ireland.

The inter-war years saw record unemployment in Britain (except the neutral Irish Republic) and a horror of repeating the experiences of the war that led Britain's leaders to be over-cautious in their dealings with the new generation of dictators that had arisen in Europe. A Second World War followed, and Britain at one stage was completely isolated.

The post war years saw uprisings for independence in many colonies. The years 1948-1971 saw most of the UK's colonies gain independence.

During the Cold War, Britain's position as the "Unsinkable Aircraft Carrier" led her to become ever closer to the USA, both in economic terms and in terms of the sheer number of U.S. forces based on the island.  Simultaneously, though, she often sought closer ties with Europe, attempting several times to join the European Economic Community before being admitted in 1973. 

The United Kingdom was recognised throughout the industrial world as an industrial powerhouse, although the UK's days as a political and economic world power were over. By far the greatest economic development affecting the UK during the mid 20th century was the discovery of large reserves of oil and gas under the North Sea extending from north-east England to the Shetland Islands.

Following a vote by the Scots and the Welsh, legislation was passed to create a new Scottish Parliament, the first in 300 years, to legislate on behalf of the Scottish People and a Welsh Assembly to represent the views of the Welsh electorate. Northern Ireland also has a devolved assembly. The devolution settlements of the late 20th century have, ironically, left England, the largest of the nations within the United Kingdom without its own dedicated legislature, although, at the time of writing (2014) there is a large push for Her Majesty's government to become federal.