But no Blair speech would be complete without one howling whopper. Nobody in British politics (he cried) would — whatever Mr Howard claims — accuse those who raise the issue of immigration of pandering to racism. Mr Blair then accused Mr Howard of pandering to racism by raising the issue of immigration.

Mr Howard should stick to his guns. Immigration matters to people. Fear, in a democracy, should be acknowledged, and politicians and journalists who respond to public anxiety by changing the subject are the very opposite of responsible. They risk losing their audience and their authority to less scrupulous individuals.

I come reluctantly to this conclusion, but in the end emphatically. I like to think of myself as being on the civilised Right. Speaking among ourselves the civilised Right sometimes say that ordinary people don’t know what’s good for them. The liberal Left find more tortured ways of expressing the same thought: the people are deluded by a false consciousness insinuated into their minds by the populist media. Both we and they blame the red-top press. We have both been wrong.

As Mr Blair seems to have recognised, where immigration is concerned, it is time to stop blaming The Daily Mail. If we don’t like its readers we had better say so, but to blame their opinions on their newspaper contradicts everything that politicians and journalists are daily taught by our experience: that you cannot tell people what they are not disposed to hear.

If media propaganda really did form people’s likes, dislikes and opinions then the overwhelming majority of the British electorate would be more than relaxed about immigration: they would be begging for more of it. For three decades the airwaves have been as packed as the newspaper opinion columns with reassuring news and commentary about the enrichment which immigration can bring.

If a few media voices have struck a sourer note, then in terms of column-inches or airtime-minutes they are a tiny minority. Yet they loom large in the national imagination. Why? We on the civilised Right and liberal Left must stop trying to elbow the evidence from our thoughts. We must acknowledge and explain the stubborn and aggrieved persistence of a popular consensus that Britain is overcrowded, and that the sudden expansion of cultures that are strange to us is bad for a nation.

And Mr Howard is right. It’s all about numbers. I really don’t think colour is any longer at the root of popular anxiety.

We are outgrowing the colour prejudice of the 1950s and 1960s. Among Londoners I hear Albanian asylum-seekers, Bosnian beggars and Eastern European economic migrants spoken of in precisely the same resentful or angry terms as might be used of immigrants whose skins were a different colour. Among ordinary white Londoners I hear Asian and black Britons spoken of with affection, respect and humour — indeed, not really spoken of as though they were “other ” at all. Mixed marriage, mixed company, mixed office outings, mixed pub-crawls are now so much the order of the day in big British cities that the very expression “mixed” sounds faintly silly. As an issue, colour is fading.

So let us, then, agree that a very large number of voters have serious anxieties not about skin colour but about the rapid growth of sub-cultures by which they feel intimidated and some of whose values they dislike; troubled that such groups are stretching the resources of the State; and troubled by the fear that even if existing numbers can be absorbed, far greater numbers may follow. Assuming that a political leader acknowledges that this popular feeling does exist, how is he to answer it?

One answer has been Mr Blair’s response, significantly modified yesterday. The Prime Minister has been replying, first, that the situation is under control but that he cannot set any limits; secondly, that immigrants bring needed skills and contribute to economic growth; and, thirdly, that many immigrants do jobs that no native British people can be found to do.

These are fair points but they are open to challenges that cannot be called racist. If immigration is on balance beneficial why try to control it at all, as the Government insists it is doing? If, on the other hand, a certain amount of immigration is beneficial but not too much, then what figure — however approximate — does the Government have in mind and why can they not debate it, set it and aim for it?

Mr Blair’s reply is beginning to fray. True, ceilings and limits do sit uneasily alongside a fluid situation, and we cannot predict where the next tyrant will strike or how many boatloads of asylum-seekers that may bring; nor can we predict precisely the demands our economy may make for skilled immigrants. But such arguments are true across a wide range of government provision — of hospital beds, for instance. So what you do is make working assumptions. We could do so with economic migration.

As for the Geneva Convention on political refugees, again Mr Howard should stick to his guns. Mr Blair’s protest yesterday that no one country can derogate is hollow. What a British threat to pull out would do would be to trigger a complete and multilateral reassessment of this obsolete accord, which many countries would welcome but none has dared to suggest.

The same is true of the present right to bring in dependants. No leading British politician has yet dared to take head-on the challenge of ending arranged-marriage migration. Denmark has. In time Britain will. There was a fascinating hint in Mr Blair’s speech yesterday that he is thinking about such ideas. It would be ironic if Mr Howard’s election campaign pushes Labour into a proposal that the Tories have so far shrunk from voicing.

Labour’s arguments, furthermore, about jobs, skills and growth strike me as questionable. Among the questions are these: are there really jobs that native British workers won’t do — or is it that they won’t do them for the wages on offer? Immigrants will work more cheaply but this surely cannot be how we should be getting our cabbages picked or our post delivered: by undercutting wage rates. Mr Blair seems to have conceded this yesterday. In bringing down the barrier on cheap labour, incidentally, he undermines his own argument that the labour market cannot be predicted.

As for skilled migrants, can importing trained people really be the structural solution to skills shortages, even if it helps in a crisis? And isn’t there a danger that we shall stop paying to train young British people if pre-trained labour keeps arriving free of charge at Dover? Economic migrants are good for growth because they are mostly of working age but, again, importing fit young workers surely cannot be the structural answer to Britain’s need to educate a younger generation and sustain an ageing population? Tomorrow, today’s immigrants will be pensioners.

The only possible answer is Mr Howard’s: to set a limit. By agreeing that Britain should move towards an Australian “points” system, Mr Blair half-concedes the logic. Like the A- level pass-mark, a points system can be adjusted to deliver an approximate set quota of successful candidates. Now all we have to do is persuade him to tell us what that number will be.

The Conservative Party may not win this election, but it is winning the argument. Whoever forms the next Government, immigration limits will be on the agenda. This is not about colour. It was Mr Blair who tried to play the race card yesterday.

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