By Mark Easton
Home editor, BBC News
A survey by the Joseph Rowntree Foundation has sampled the attitudes of migrants coming to the UK from eastern Europe.
What does the study tell us about this section of the British population?
Many people have made the long bus trip from places such as Poland
Officials may hazard a guess, but the truth is we don't know how many eastern European migrants are working in Britain today.
The latest official figure of 510,000 registered workers doesn't include the army of self-employed plumbers and builders who have made the 40-hour bus journey from Warsaw, Vilnius or Prague.
Nor does it include the thousands of students who have taken advantage of EU expansion to expand their minds and knowledge.
The figure also does not reflect those eastern Europeans who are working here without proper papers.
But critically it doesn't take account of the many migrants who have already left Britain and returned home.
The Joseph Rowntree Foundation report - Changing Status, Changing Lives? - interviewed hundreds of migrant workers from eastern Europe working in low-paid jobs in Britain.
For the first time we get, not so much a portrait, as a rough sketch of what this wave of new immigrants looks like. Average age 27, the vast majority are single.
The data, which is indicative rather than representative, suggests there is just one dependent child here for every eight to nine migrants.
Very few workers arriving describe themselves as fluent in English - a quarter admit they have only basic English or none at all.
And yet only one-third of those surveyed said they were taking, or had taken, English classes.
The poorer their language skills, the less likely that they had attended a course.
Most of this group plan to work, earn, send the money back home and follow it eastwards after a couple of years.
The survey suggests tension between different groups in the UK
But what the survey does suggest is that having arrived, migrants' plans change.
When their countries first joined the EU, 26% of women and 22% of men said they'd stay indefinitely.
Six months later the figure had risen to 35% of women and 26% men.
Although the numbers surveyed are small, the researchers conclude that "the probability that some temporary migrants will in practice remain in the UK for a number of years or settle permanently is the reality that must be taken into account".
The survey also found evidence of tension between different ethnic groups - "Strong expressions of prejudice against other migrants and against some British ethnic minorities."
A Slovak cleaner was not alone in suggesting there was resentment especially against Poles who, she said, work illegally for less than the minimum wage.
A Ukrainian woman, herself working illegally to support her young daughter, claimed Polish migrants would "sell" her people, shopping them to the Home Office to get jobs or accommodation.
Migrants also experience prejudice from the UK population. Just 39% of those surveyed felt British people treated them equally.
Despite such tensions, this report finds that most migrants end up staying longer than they'd planned and almost all of those who leave say they plan to return.