John Rentoul: Arrogant, presidential, isolated. The myths about Blair are set in stone

In June, Davis said: "The test of everything is how well it helps the whole society but in particular the bottom half of society." You could sort of see what he was getting at - another reworking of the idea of "compassionate conservatism" - but it sounded no more convincing than Iain Duncan Smith's curious attempt to try on John Smith's mantle of social justice.

By the time he gave an interview to The Daily Telegraph in July, however, Davis had refined his position. "I don't want Britain to be a more equal country; I want it to be a more mobile society." It was a clever sound bite, and rather more firmly based on existing perceptions of the Conservatives as the party of aspiration.

It suggested that Davis does not want greater equality for its own sake - the surprising implication of Major's answer a decade earlier - but as a by-product of a more open society that gives more opportunities to the poor. Davis picked up a half-understood news story already hardening into conventional wisdom: "Social mobility has gone down. People have got trapped." This was a reference to an academic study that compared the fortunes of two groups, one born in 1958 and one in 1970. It found that the earnings and status of those born in 1970 matched those of their parents more closely than those born earlier. In other words, that social mobility had declined.

This was widely reported as proving that Britain had become less socially mobile under Tony Blair. The Guardian, the house journal of left-wing pessimism, declared, for example: "Social mobility has not just silted up, but has gone into reverse." A moment's thought should confirm that the study showed nothing of the sort. By the time Blair became Prime Minister, the second sample were aged 27 and the factors that influenced their socio-economic status were beyond the reach of any government deprived of the advantages of time travel.

But who is interested in facts? Last week saw the headlines, "Inequality widens under Blair" (Telegraph) and "Wealth gap between rich and poor has widened since 1997" (Independent). Both newspapers were reporting a study published by the Office for National Statistics called Focus on Social Inequalities. The Independent at least, had the honesty to report that the figures used in the study were six months old. What it did not say, though, was that the figures showed that inequality of incomes has remained unchanged since the mid-1990s.

The headlines were based on a sentence in the study that pointed out that incomes had risen substantially in recent years, and that this percentage increase was worth more to those on high incomes than to those on low incomes. To report that as "inequality widens" is the sort of statistical howler that would - one hopes - still get candidates marked down in their GCSE maths. But it allows people to believe what they want to believe, which is, that under the "Thatcherite" Blair, Britain continues to become a less equal country.

Never mind that most of the policies with a direct bearing on the issue are the responsibility of the allegedly more left-wing Gordon Brown. Never mind that it is a heroic achievement to hold the line against rising inequality in an economy open to world trade, and relatively open to world labour markets. (Only Polly Toynbee in The Guardian seems to recognise that there may be a conflict between the left's demands for more equal pay and its support for liberal immigration policy.) Never mind that millions of children and pensioners have been lifted above a poverty level defined in relation to average earnings. Never mind all that.

How much easier it is to accuse Blair of betrayal than to devise vote-winning policies that could help close the gap between rich and poor. If policies do seem to work, they are misrepresented to "prove" that they don't. One of the most important ways to tackle inequality at source is in schools. So the newspapers report that the children of the better-off are widening the gap in performance over the children of the poor. Not true. The gap in GCSE performance between children from the top and bottom social groups was 44 percentage points in 1992, rose to 49 points in 1998 and fell again to 45 points in 2002. It is not great, but it is headed in the right direction, and it raises the question of why so many on the left oppose city academy schools, most of which last week reported sharp improvements in GCSE results in deprived areas.

But Blair has reached that point in the life cycle of politicians where people have formed their view of him and it is impervious to facts. Last month, before the London bombings, The Mail on Sunday reported as fact that the police had started to close Parliament Square to traffic for 20 minutes every Wednesday, while Blair was driven the 300 yards from Downing Street to the House of Commons for Prime Minister's Questions. It is not true, as a telephone call to the Metropolitan Police press office quickly confirms. Yet it has already become part of the mythology of an arrogant, presidential Blair isolated from ordinary people who risk being blown up on the Tube.

The other part of the myth is that he is a traitor in the mould of Ramsay MacDonald, an interloper who hijacked the Labour Party in order to win power and who had no interest in furthering its historic mission of achieving a more equal society. Yet who was it who asked John Major that unusual question 10 years ago, and who, by implication, also accepted that it was the Government's responsibility to reduce inequality? Tony Blair, that's who. And later this year he is likely to be up against a Conservative leader who says explicitly that he doesn't want Britain to be a more equal country.

Those who do care about equality ought to prepare themselves for the battle ahead. They should not be bamboozled by a media bias that is much more interested in stories that say "Blair's a failure" than good-news stories about Labour's successes. Let battle commence, but let it be on the basis of fact, not myth.