Leading article: The real reason why Britain needs immigrants

Immigration is a subject beset by myths - on both sides. Last week's official estimates, both for the number of central European workers that have come to Britain since EU enlargement two years ago and for the total UK population, have been filtered through those myths. The result is that the significance of some important changes has been missed, as the advocates and the opponents of immigration have fitted the figures into their view of the world.

Unfortunately, the myths of the anti-immigration tendency are more emotive, and more easily presented as "just common sense". We suspect that most readers of this newspaper will not need to be persuaded of the untruth, or at best irrelevance, of the staples of the anti-immigration argument. We have been told many times over the past week that Britain is overcrowded. That is an entirely subjective term. Some of us might prefer to live at Iron-Age population levels on these (reforested) islands - provided, of course, that we were among the lucky four million who would not need to be deported. Yet most of us live at high densities in cities - roughly the same densities in which humans have huddled since they made the lifestyle choice of farmer over hunter-gatherer. And there are many countries or parts of countries around the world with comparable or much higher population densities.

Then the argument shifts: too great an influx will put pressure on our public services, it is said. Generally, that has not been true of the arrival of workers from the new EU member states. There have been some striking cases of, for example, Roman Catholic primary schools taking whole new classes of Polish children, but the real story is that of the professionalism with which the education system has responded to unexpected changes. The gain to the National Health Service of staff from abroad far outweighs the additional burden of treating immigrants, most of whom are of working age. Generally, immigrants give a great deal more in taxes than they take in public services.

Indeed, on the overall economic benefits of immigration, the supporters of a liberal policy, led, we like to think, by The Independent and The Independent on Sunday, have conspicuously won the argument. The antis have been forced on to the defensive, forced to declare that they do not want these benefits, or that they come at too great a long-term cost. It is at this point that the anti-immigration argument slides off into a confused ramble about multiculturalism, integration and social cohesion.

The link between the population growth and multiculturalism, which has become a code word for the threat from home-grown terrorism, is tenuous. The main source of growth that took the population over the 60 million mark has been white, nominally Christian migration from within the EU. The problem of the alienation of some British Muslims is an important one, and we welcome the attention paid to it at cabinet level by Ruth Kelly (even if we are sceptical about a top-down approach to the issue based on co-opting "community leaders" on to task forces). We adhere to the view that this country has been vastly enriched, economically and culturally, by non-white immigration, just as it has by every wave of new arrivals in its polyglot history. But the debate about the British Muslim identity has almost nothing to do with arguments over current immigration policy.

The Prime Minister's attempt to link the two issues as facets of the single phenomenon of "globalisation" does not really work, even if his intentions are admirable. He has made the case in recent speeches for Britain to remain an "open" rather than a "closed" society and economy, and his commitment expressed by a Downing Street spokeswoman yesterday to do so "with renewed vigour" now that he is back at work is welcome. The unavoidable choice that he faces in immigration policy is the question of whether to allow Romanians and Bulgarians to come here to work on the same terms as Poles and Czechs. If he means what he says, he should have the courage of his "open" convictions. If Polish and Czech workers have been good for this country - as they have - then Romanians and Bulgarians should be too.

Yet the supporters of immigration have their myths as well, and they need to be dealt with honestly if the advantage is not to slip back into the hands of the xenophobes. Clearly, immigrants bring cultural diversity and their age profile offsets the ageing of mature societies, in addition to the measurable economic benefits. But one of the pro-immigration myths is that the potential demand for migration within Europe is trivial. The Government forecast that 15,000 workers might come to Britain in the year after the new EU members joined in 2004. This prediction was partly based on the experience of Spain and Portugal joining the European Community in 1986. But the gap between their living standards and ours then was smaller than that between ours and those of the former communist bloc now. If there is an economic advantage to migration - for the migrant, for his or her employer and for the host society generally - then it will be greater if the disparity in wages is wider. Hence last week's estimate that, in the past two years, more than 600,000 workers have actually come from the new EU member states. We British should be delighted that our economy is so flexible and dynamic that it can generate more than half a million new jobs in such a short time. That is the big story of last week that has been obscured by the myths. Britain has not seen employment growth on that scale in recent memory.

There is no question that such changes produce a strong net benefit to the British people. But the scale of the change is such that there are bound to be adjustment costs, and it would be foolish to pretend that everyone in Britain benefits equally or even at all. The rise in unemployment confirms that some of us are losing out. In fact, the rise in the jobless figures has been modest, and may be a lagging indicator of a slowing in the economy some time ago. But it cannot be denied that at least some of the new jobs would have gone to British workers had immigrants not been available. And the sectoral earnings figures, also published last week, confirmed that wages in several unskilled and low-skilled jobs have fallen.

Equally, while we supporters of immigration reject the idea that Britain as a whole is overcrowded, there are bound to be consequences for the housing market, with demand increasing so much more sharply than can be matched by supply. While there is no national housing shortage, high prices and rents in the South-east are likely to continue to distort the UK economy for the foreseeable future.

Then there are the effects on the economies and societies of the countries, many of whose most industrious and most enterprising workers are being attracted here. Poland, Romania and Bulgaria all experience the opposite phenomenon to us of declining populations. In the long run, market forces may even that out - already Britons and Germans are buying up property across central and eastern Europe.

But, as Keynes said, in the long run we are all dead, and in the meantime governments need to act to ensure that the benefits of migration are shared equitably, including among the current losers.

With that proviso, we should be bold enough to take on the greatest of all the anti-immigration myths - that to allow immigration is to betray our children. On the contrary, to prevent economically beneficial immigration would be the greatest betrayal of our children, by simultaneously denying them the fruits of prosperity and saddling them with the burden of an ageing population.