Life is, thank God, full of incongruities. One of which is that many of those who write in to the comments part of the website complaining about too many foreigners coming to the United Kingdom then give their location as somewhere abroad.

The very first reader’s contribution to last week’s Aaronovitch-Parris debate on the Blair years, for example, asked simply, “What about immigration and the failure to control the borders?”, before signing off as “Mike, Sydney, Australia”. It is amazing how often Gwen from Spain and Don from the Dordogne take up mouse and keyboard to moan about people doing in the UK what they have so obviously done themselves in some other country.

Their unconscious message is: you, alien interloper; me, seeker after better life. Yet this blitheness in the face of an obvious contradiction doesn’t make Gwen and Don wrong.

A few weeks back I received a free pamphlet from one of the fustier right-wing think-tanks (the sort that campaigns constantly for fewer people to go to university), arguing that while Britain had absorbed previous waves of immigrants, this time the very existence of the UK was under threat. “Now our culture and our nation,” stated the author, “are in danger of fragmenting as large immigrant populations decline to integrate.” Back in 1905 the TUC had it wrong about the Jews and in ’68, one imagines, old Enoch was just foolin’ with his bloody Tiber. Today, according to the boffins at Civitas, it’s for real.

Civitas’s case is in some ways confusing – the pamphlet speaks about the “seemingly reckless pace and scale on which immigration has recently been allowed to proceed”, without ever spelling out what the problem with this is supposed to be. Is it racial disharmony? Potential ethnic conflict? The inability of different cultures to knock along together? The difficulty for the latterday Enochs is, to be absolutely blunt, that the greatest number of new migrants by far are simply not exotic enough to scare the indigenous population into the arms of the self-de-Hitlerising racists of the BNP (all that antiJew stuff and bombmaking being put down to youthful high jinks) or even the embrace of the cuddly Von Papen chauvinists of UKIP. Who feels intimidated by a barful of long-legged blondes from Krakow? Apart from Sir Patrick Moore, that is.

The irony is that the Krakowian waitresses do indeed represent part of the greatest and fastest shift in population in the country's history. In Enoch’s time there were never more than 50,000 Commonwealth immigrants coming in per year. In two years, from mid-2004 to mid-2006, 600,000 people from abroad came to work here, mostly from Eastern Europe. So when it was announced yesterday that four local councils had written to the Treasury to say that the Office for National Statistics was undercounting their immigrants, I had no trouble in believing it might be true, and not just another ploy to get more money. The councils say that, by any measurement, there are simply more people in their boroughs than there are supposed to be.

The straight numbers only tell you so much. 40 per cent of the newcomers are under 24. Most do not come here to live, and many leave within months. A substantial number now go to areas of Britain where there has never previously been any large-scale immigration, such as East Anglia. They work full-time and for relatively low wages.

Blonde or not, the numbers involved have inevitably led some people to argue that “something must be done.” I rather liked a recent headline in which it was revealed with some horror that Tony Blair has admitted that “the UK has no policy on controlling the size of its population”, as though it was his job secretly to have cooked up a Population Plan for how many of us there should be.

Once, 30 or so years ago, I might have bought the idea of central planning. Didn’t it win us a war? Didn’t it propel Russia into the Space Age? Then I visited the offices of Gosplan in Moscow and the whole notion didn’t seem quite so attractive any more. It is funny, therefore, to see how – when it comes to that most intractable item, the human desire to go where its fancy takes it – sections of the Right seem to want to take Mao as their mentor. Nigel Farage, UKIP’s leader, wants “zero net immigration”, a concept whose policing would make Beria blench. “Yes, we’ve had one die in Oldham, so you can come in . . . whoops, no, sorry, Mrs Baxter in Stoke has just had twins.”

But is the Conservative Party’s notion, as outlined in its policy paper Controlling Economic Migration, any more realistic? This calls for a kind of national economic assessment, so loved by the early ’80s Footite Labour Party, except this one would be for population movement. There would be “annual limits” on economic migration, worked out in yearly consultation with local authorities, businesses and sundry others, somehow “taking into account” the need for labour, the availability of public services, the effect on the environment and something slippery called “community cohesion”. David Cameron couldn’t tell anyone what sort of figure a limit might be set at, but it would be “significantly less” than now.

Think about this. We will have a national plan for immigration that would try to second-guess the decisions of a zillion local businesses about who they want to employ and when, would attempt to thwart the ambitions of hundreds of thousands of qualified workers, and still expect our economy and our society to remain as dynamic as they are today. And all of this will be on the basis of a best guess made in committee by people who may have no idea what is going on in the world. We should bring back the Prices and Incomes Commission while we’re about it, and renationalise a few key industries.

Am I alone in seeing the modern shades of Canute’s courtiers urging the king to hold back the tides? To keep this nonpartisan, let’s also attack the Government’s idea of a points system for incoming workers. Would such a system be better at deciding the needs of the economy than Britain’s employers? No.

Governments – except for genocidal ones – can no longer control demographic change. To act otherwise risks incurring unreasonable cost or causing intolerable hardship. So the job now – the huge job – is to predict such change and manage it. The rest is Stalinism.

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