By Mark Easton
Home editor, BBC News
Almost two-thirds of people in Britain fear race relations are so poor tensions are likely to spill over into violence, a BBC poll has suggested. So what does it say about race relations in Britain?
We have witnessed in Britain over the past decade a level of immigration greater than at any time in our history.
A million have recently come from Eastern Europe, but the migration to our shores has been from all parts of the globe.
Ethnic tensions have occasionally spilled over into violence
Yet this extraordinary social change has been conducted with remarkably little hostility or public opposition.
Our experience is testament to the tolerance and adaptability of the British people.
There have been times in the last ten years when racial and ethnic tensions have spilled over into violence.
Street fighting between black and Asian communities in the Lozells area of Birmingham in 2005; race riots in Bradford, Burnley and Oldham in 2001 - segregated communities in conflict.
Is this what almost two thirds of the public think is likely to happen when they talk of tension leading to violence?
Or are they imagining scuffles on a Saturday night?
We cannot be sure, but government ministers accept the "churn and change" associated with record immigration is leading to problems.
Social cohesion remains strong, they insist, but a team of officials have been instructed to monitor tension levels around the country.
This weekend sees the 40th anniversary of Enoch Powell's inflammatory "rivers of blood" speech, which achieved the opposite of its intention.
It forced the issue of immigration off the political agenda, making it a no-go area for debate by fusing it with the issue of race.
Margaret Thatcher was accused of racism in 1978 when she suggested some communities might feel "swamped" by immigration.
In 2005 Conservative leader Michael Howard was also said to have "played the race card" when he suggested some communities could not deal with the pace of immigration.
"Politicians of the left attempted to intimidate people into not raising it by crying racism", he told me this week.
Just five months ago, a Conservative candidate in Birmingham, Nigel Hastilow, was forced to stand down by David Cameron for suggesting "Enoch Powell was right" in saying uncontrolled immigration would "change our country irrevocably".
The architecture of the debate was set by Powell's speech in suggesting greater immigration would lead to greater social turmoil.
"Like the Roman, I seem to see the River Tiber foaming with blood," he said.
But this new poll suggests the public no longer mixes the issues of race and immigration.
The proportion who admit to feelings of racial prejudice has fallen to 20%, the lowest score ever recorded to the question.
But six out of ten think there are too many immigrants and half thought the government should encourage immigrants to return to their country of origin.
Immigration has become one of the most salient political issues with the public and, in recent months, ministers have felt more comfortable in raising concerns.
Home Office Minister Liam Byrne has reflected on the cultural, social and public service pressures that can go hand in hand with immigration.
These are statements that bear uncanny resemblance to observations denounced as "racist" only a few years ago.
Trevor Phillips, now chair of the Equality and Human Rights Commission, agrees that no white public figure could have got away with questioning multiculturalism as he did a few years ago.
"We have to look at this in the round or we go back to the place where Powell put us, which is that we cannot talk about this honestly and in all its facets," he told me.
A question of colour?
Perhaps the most important factor in allowing a rational debate about immigration has been its changing nature over the past few years.
The issue has been dominated by the arrival of migrant workers from Eastern Europe.
They are different from the waves of immigrants who came from the Indian sub-continent and the Caribbean.
Firstly, they say they have no desire to settle here. Second, their motivation is purely economic.
Thirdly, and perhaps most crucially, they are white.