The early story of the British Isles is one of colonisation. Firstly, celtic and pict tribes arrived and formed the first communities in the British Isles.
Then came the Romans. In 250AD, Rome sent a contingent of black legionnaires, drawn from the African part of the empire, to stand guard on Hadrianís Wall.
There is no evidence that these men stayed in Britannia and when the Romans finally quit in the fifth century, the way was clear for the Germanic tribes that would slowly become the English.
Four hundred years after the Jutes, Angles and Saxons colonised modern-day southern England, the Vikings arrived, bringing a distinctive new influence to the cultural pot. The Vikings' sphere of influence was northern Britain and modern-day East Anglia.
The most dramatic of these immigrations was the Norman Conquest in 1066. The Normans, descended from Vikings who had settled in France, brought with them their early-French language which would fundamentally change the direction of English, government and law. To this day, a number of Parliamentary ceremonies can be dated back to the Franco-Norman era.
The first Norman king, William the Conqueror, invited Jews to settle in England to help develop commerce, finance and trade.
During the Middle Ages, the few black faces in Britain appeared to be entertainers linked to royal entourages.
African drummers lived in Edinburgh in 1505. In London, Henry VII and his son Henry VIII both employed a black trumpeter named in one scroll as "John Blanke".
But conquest of the New World changed everything. As Europeans
established plantations in the Americas, they needed cheap labour.
They found it by buying into the slave trade that already existed in northern Africa.
John Blanke as he appears in a scroll.
Picture copyright: College of Arms, London. Reproduction prohibited.
The Portuguese and Spanish began buying slaves from African and Arab merchants and taking them to work the plantations. In 1562, John Hawkyns made England's first foray into the trade when he sold 300 West African men to planters in Haiti.
A few years later, black slaves began appearing in wealthy households in England. When wealthy plantation owners sent their children to schools in England, they would sometimes send slaves too.
The legal status of these immigrants was vague because their arrival was tied to their English owner and their freedom appeared to relate to whether or not they were Christian.
There was some legal debate on whether or not a man brought to a free country could be anything but free. But it amounted to nothing and the trade grew.
In the early eighteenth century, treaties between European powers changed the political map. The United Kingdom, as it had now become, won more access to the New World and its riches.
Merchants from Liverpool, Bristol, Glasgow and London rapidly expanded the slave trade and brought goods and riches back to Britain, wealth that would bankroll the coming industrial revolution.
They also increased the number of African men, women and children resident in Britain. Approximately 14,000 black people lived in England by 1770.
But few of them had real freedom and a movement to abolish slavery emerged.
In 1772, the abolitionists brought a famous case to the courts. The judges were reluctant to rule on slavery, not least because of its economic importance to the UK.
The abolitionists won a minor point that a slave could not be forcibly transported from England. But in practice it made little difference to their lives.
Eventually the abolitionists became one of the largest popular protests of British history and the end of slavery in Britain came in two stages.
In 1807, Parliament banned the trade - but not slavery itself. In effect, slaving ships still operated, the only difference being that captains threw their captives overboard if they were in danger of being caught.
In 1833, Parliament finally banned all slavery across the British Empire - though later investigations showed that tied labour still existed in many areas including India.
Abolition meant a virtual halt to the arrival of black people to Britain, just as immigration from Europe was increasing.
There were some notable exceptions. Wealthy families brought Indian servants to Britain. Cama and Company became the first Indian merchant to open offices in London and Liverpool. Black and Chinese seamen began putting down the roots of small communities in British ports, not least because they were abandoned there by their employers. Between 1830 and 1850, tens of thousands of Irish arrived in Britain, fleeing poverty at home.
Britain's first non-white MP, Indian Dadabhai Naoroji, was elected to the House of Commons in 1892. A few years earlier, Arthur Wharton, born in modern day Ghana, became Britain's first black professional footballer.
During the two world wars, hundreds of thousands of men from across the Empire fought for Britain. India alone provided 1.3m soldiers for the First World War, 138,000 serving on the Western Front.
During the Second World War, almost 60,000 British merchant seamen came from the sub-continent. Some of the men stayed in Britain during the inter-war years, forming small communities in ports.
Bengali seamen, known as Lascars, went to work in Scottish collieries but were subjected to racial prejudice.
They were not the only ones. There were no clear rules on immigration but officialdom appeared not to approve.
Government feared the impact of black faces in white Britain - not least after a spate of race riots in 1919.
At the end of the Second World War there were work shortages in Europe and labour shortages in Britain. The government began looking for immigrants.
Some 157,000 Poles were the first groups to be allowed to settle in the UK, partly because of ties made during the war years. They were joined by Italians but it was not enough to meet the need.
Many men from the West Indies had fought for the "mother country" but returned to civilian life with few opportunities.
Their sense of patriotism, coupled with the need to find work, steered them towards the UK.
Despite an apparent official reluctance to allow immigration from the fast-disappearing empire, the government could not recruit enough people from Europe and turned to these men.
On 22 June 1948, the Empire Windrush docked at Tilbury in London, delivering hundreds of men from the West Indies.
Many had returned to rejoin the RAF. Others had been encouraged by adverts for work.
The day marked what would become a massive change to British society - the start of mass immigration to the UK and the arrival of different cultures.
As mass immigration continued in the 1950s, so did the rise of racial violence and prejudice. Many areas including Birmingham, Nottingham and west London experienced rioting as white people feared the arrival of a black community.
On one hand, these men and women had been offered work in a country they had been brought up to revere. On the other, many were experiencing racial prejudice they had never expected.
Legislation had allowed people from the Empire and Commonwealth unhindered rights to enter Britain because they carried a British passport.
Under political pressure, the government legislated three times in less than a decade to make immigration for non-white people harder and harder.
By 1972, legislation meant that a British passport holder born overseas could only settle in Britain if they, firstly, had a work permit and, secondly, could prove that a parent or grandparent had been born in the UK.
In practice, this meant children born to white families in the remnants of Empire or the former colonies could enter Britain. Their black counterparts could not.
While government was tightening the entry rules, racial tension meant it had to try to tackle prejudice and two race relations acts followed.
In 1945, Britain's non-white residents numbered in the low thousands. By 1970 they numbered approximately 1.4 million - a third of these children born in the United Kingdom.
The government had greatly restricted immigration by the 1970s, but had not stopped it altogether. Some 83,000 immigrants from the Commonwealth settled in the UK between 1968 and 1975, largely through gaining work permits or obtaining permission to join relatives.
The most significant immigration of the decade came in 1972 when the Ugandan dictator General Idi Amin expelled 80,000 African Asians from the country, families who had been encouraged to settle there during the days of Empire.
Many held British passports and, amid a major crisis, the UK admitted 28,000 in two months.
In 1976 the government established the Commission for Racial Equality, the statutory body charged with tackling racial discrimination.
In 1978 Viv Anderson became the first black footballer to be selected for the full England team and went on to win 30 caps.
By the 1980s Britain's immigration policy had two prongs. Firstly, there were strict controls on entry.
Secondly, the state said it would protect the rights of ethnic minorities. Critics suggested that the two prongs gave conflicting signals on the place of the immigrant communities - and their British-born children - in society.
As manufacturing declined, work permits were harder to get unless you had specialist skills or professional trading.
This meant that the largest immigrant groups were Americans (to banking and industry), Australians, New Zealanders and South Africans making use of family-ties entry rules, and South Asian men and women entering the medical professions.
The riots of 1981 were largely sparked by racial issues. In Brixton, the spiritual home of Britain's afro-Caribbean community, youths rioted amid resentment that the police were targeting more and more young black men in the belief that it would stop street crime. Similar riots followed in Liverpool and the Midlands. The subsequent Scarman Report found that "racial disadvantage is a fact of current British life".
On 11 June 1987, the face of British politics changed when four non-white politicians were elected at the same General Election. Today there are 12 non-white MPs. Campaigners say that equal representation would require at least 55 black MPs in the House of Commons.
The inquiry into the police's handling of the 1993 murder of black teenager Stephen Lawrence led directly to new anti-discrimination legislation passed in 2000.
In the years following the fall of the Iron Curtain, a new movement of people began, some fleeing political persecution, others seeking a better life in western Europe.
The growth of asylum seeker applications contributed to a new growth of immigration to the UK. Between 1998 and 2000, some 45,000 people arrived from Africa, 22,700 from the Indian sub-continent, 25,000 from Asia and almost 12,000 from the Americas. Some 125,000 people were allowed to settle in the UK in 2000.
But the rise in asylum seeker arrivals has seen a rise in racial tensions.
In May 2002 the far-right British National Party won three local council seats, a year after racial tensions and were blamed for riots in northern towns. The government's plans for a new nationality and immigration legislation, including a possible citizenship test, sparked new controversy.
Fifty years after the start of mass immigration to the UK, questions are still being asked about whether or not the UK can become a multi-ethnic society at ease with itself - or whether there is still a long road to be travelled.