There was major immigration in the 20th century. After the war, many immigrants came to Britain from the former colonies of the British Empire. They came to escape poverty or problems at home and were originally welcomed because of their contributions to the war effort.
In 1948, the Empire Windrush brought the first immigrants from Jamaica.
In the 1960s, many Indians and Pakistanis came to work in the textile mills of Yorkshire and Lancashire.
In 1968, Kenyan Asians came to Britain when they were expelled from Kenya.
In 1972, Ugandan Asians came to Britain when they were expelled from Uganda.
The number of non-white British people rose from 400,000 in 1961, to 9.1 million in 2011.
Ugandan Asians arriving in the UK
In 1993 the European Union (EU) brought in the 'single market', which gave EU citizens the right to live and work anywhere in the EU. By 1997 a million people had come to Britain from the poorer countries of eastern Europe, especially Poland.
Immigrant groups faced discrimination and violence, for example:
In the 1958 Notting Hill riots, British youths attacked West Indian youths.
In 1968, the politician Enoch Powell gave a speech talking about a time when the black man will have the whip hand, and predicting rivers of blood.
In 1981, there were race riots in London and Toxteth in Liverpool. There were more race riots across Britain, but especially in Brixton in 1995, and Bradford, Oldham and Burnley in 2001.
Notting Hill race riots
During the 20th century, as the population continued to grow and pressure on resources increased, the British government passed a number of laws to try to reduce the inflow of immigrants:
An anti-immigration campaign grew up which resulted in the Aliens Act of 1905, which refused entry if an immigrant was a criminal or could not work.
Between 1962 and 1981, a number of immigration acts made it gradually more difficult to come to live in Britain.
In 2005, the government ruled that anyone applying to settle in Britain must have passed an English speaking test, and also a 'life in the UK' test.
Immigration had a huge effect on the United Kingdom:
Immigrant groups formed strong communities, eg Chinatowns in various cities like in Manchester where it is a cultural icon. Southall in west London has a large and thriving south Asian population.
Immigrant groups have brought economic benefits and specialist knowledge to Britain. Doctors and scientists work in British hospitals and universities. Immigrants have helped resolve labour shortages in the textile mills, and work in seasonal industries such as agriculture.
In 1965, 1986 and 1976 the government passed Race Relations Acts to prevent racial discrimination.
In 2011, about 14 per cent of the population belonged to an ethnic minority.
Groups such as the British National Party and the English Defence League formed to try to stop immigration.
Some areas of the UK, such as Newham in East London, now have a higher number of non-white people than white people. Different religions are also becoming more widespread.