Only 380,000 east European migrants have registered for national insurance purposes since the EU was enlarged in 2004 - far fewer than previous estimates of the number who have come to work in the UK.
The figure suggests that either the Government has a major problem on its hands, with almost a quarter of a million EU migrants working illegally, or that the Home Office estimate of 600,000 was grossly overstated.
Richard Exell, the TUC's labour market specialist, said: "We have always said that the 600,000 figure was too high, because it only counts the number who have come in; it does not allow for those who have come in, gone away, and come back. There has never been 600,000 people from eastern Europe working here."
The former Europe minister, Denis MacShane, said: "This is an astonishing figure. It shows the alarmist rhetoric of those who have been blaming the Poles and other EU nationals for taking British jobs has been false. It is one in the eye for the xenophobes and Europe-haters."
Nick Clegg, home affairs spokesman for the Liberal Democrats, said: "Once again, the left hand of Government does not know what the right hand is doing. No wonder the public is left confused when such wildly differing figures are bandied about. These statistics raise serious question marks about the sky-high figures used by Migration Watch and others."
But Damian Green, the Tories' spokesman on immigration, said: "This is quite a disturbing figure. It suggests that there are more people than we thought working without national insurance numbers. My first question is, where are the other 70,000 people who applied for work permits? Does this mean that the cowboy sector is even bigger than we thought?"
Previous estimates of the number of migrant workers from the 10 countries that joined the EU in May 2004 have been based on the fact that 447,000 have applied for work permits, and it is assumed that about half as many again are self-employed.It is illegal to work in the UK, either as an employee or self-employed, without registering for national insurance.
Unlike the Home Office's estimate of 600,000, the new figure, posted on the Department of Work and Pensions website after a Freedom of Information request, is not an estimate but an exact count of how many migrants have registered for national insurance, and which part of the world they come from.
The discrepancy will be partly made up of people who are working without national insurance numbers, either through delays in the system or because they are breaking the law. There are fears that some, unfamiliar with British law, will have been induced by cowboy employers not to register, to evade tax.
The figures also show that the number of foreign workers claiming benefits fell - confirming that the great majority of people coming in from eastern Europe are genuinely looking for work, not seeking to live off the welfare state. Before 2004, there was no great difference between the proportion of foreign workers and the proportion of the British workforce claiming benefits. Both figures were around 12 per cent. Now only 3 per cent of foreign workers are claimants, the proportion having been driven downward by the influx from eastern Europe.
The figures also show that the average age of migrant workers has fallen since the EU expanded. Before 2004, 32 per cent were under 25. That proportion has climbed to 37 per cent. About half of all migrant workers are in London and the South-east.
Danny Sriskandarajah, associate director of the Institute for Public Policy Research, said: "If you look beyond the headlines the story is not nearly as scary as some make out. We know that the Home Office figure of 600,000 is not accurate. It includes people who were here for only a very short time, and then went back. This lower figure is a much better indication of how many are here to stay."Reuse content