The supposed failure of the Government's measures to increase upward mobility has always surprised me. It was puzzling at an anecdotal level, where one could see new schools being built, more money for education in poorer areas, more teachers being employed, exam results improving, access to higher education increasing and local Surestart groups offering early support to all kinds of parents. From observation of my bourgeois peers - and myself - I could understand why there was little downward mobility, but not why so little seemed to have changed at the bottom.

Actually I knew part of the answer, but didn't have the confidence to argue it. This was that it was simply too early to evaluate the effect of government policies on long-term social trends.

There are some subjects, such as the US election and the Ross-Brand saga, that offer public, pundits and politicians the relief of instant gratification. You don't need to know anything to qualify for a discussion about the American New Dawn, and - as David Cameron proved this week - you can use the nasty phone calls incident to launch just about any opinion you want on the subject of the BBC.

But some important questions take a lot of thinking about and a lot of time to develop. Yesterday the No 10 strategy unit published a discussion paper on social mobility, before the delivery of a White Paper sometime in early 2009. The discussion paper used a variety of studies of trends in social mobility, including the most recent, as the evidential basis for its conclusions.

I've trawled through the document and it is not a piece of early-era Brown propaganda. Even so, in some places (not all) it challenges what has become the pundit orthodoxy, constructed from the reporting of a number of studies over the past five years, that social mobility in Britain has gone backward. If I could summarise the meaning of the document, it is rather that the policies put in place to try and create greater mobility are, very slowly, beginning to pay off.

The importance of this is difficult to exaggerate. As we enter a recession it would be very easy for a government of any persuasion to save money by axing expensive social programmes which, by general (if fuzzy) agreement, are not working. But what, fellow Britons, if they are working?

You may not know it, but most of the evidence you have ever seen published on this subject relates to people whose circumstances were forged in the period before 1997. There have been long-term studies of children born in 1958 and 1970, but for some reason the next cohort study began 30 years later, with the millennium cohort of 2000. This means that there is a generational research gap. I have no idea why this is, but my prejudice is that it had something to do with Margaret Thatcher's scepticism about the value of social sciences.

Let me illustrate what this means. Not so long ago I commented on one writer who described the 27-year-old Jade Goody as a product of new Labour's failed education system. I pointed out that Goody had not spent a single year at school under a Labour government of any denomination. Likewise a 25-year-old illiterate would have started primary school in 1988 and left school at 16 in 1999, two years into Labour's first term. He may represent a failure in Labour's adult literacy programme, but he says almost nothing, per se, about their schools policy.

Social mobility is usually measured by the chances of a child whose parents have one category of occupation getting a job in a different category. (Interestingly, some evidence suggests that whereas social immobility in countries such as Britain may be a product of income differences, in places such as Germany it is a product of parental social status.) Consequently it is hard to measure any group much under the age of 25.

The 1958 group was 5 in 1963 and 18 in 1976. The 1970 group was 5 in 1975 and 18 in 1988. Of this last group we know that, compared with the 1958 cohort, their social mobility had declined. But, clearly, the 2000 group is just 8 years old. We won't know about them for nearly two decades.

Of course it would be absurd to wait so long before making any interim judgments, and the best way to do that is by looking at educational attainments. It is here that there seems to be some bad and some good news. The good news is related to children born in 1990-91, and who took their GCSEs in 2006. Here there was a measurable decline in the influence of family background upon results. At this point there was enhanced mobility and kids were breaking free of their inherited limits.

The bad news was that, in the 2000 group, there were still clear differences in early cognitive development between the children of different social groups at the age of 5. But there are two things to be said here. First, this group may (and I think will) still exhibit greater mobility as measured by GCSEs in 2015-16. Secondly, things have changed even since 2005. In that year there were about 250 early-year children's centres, whereas the number reached nearly 3,000 this year.

There are other important straws in the wind. Good teaching, says the paper, makes a big difference (no surprise there) and is still disproportionately to be found in better-off areas. Now, I esteem independent school heads, such as Patrick Derham who wrote in these pages yesterday, but I do wish they'd drop this absurd pretence that - employing some of the best teachers in the land - they are somehow models of social diversity. It may be “a myth that only rich toffee-nosed children attend schools such as Rugby”, but it isn't that far from the truth either. They could do a lot more, particularly in the field of school-to-school co-operation.

But really, that's a sideshow. My point is that, given time and reinforcement, the general policy of investing in early-years, in schools, in expanding higher and further education and in adult skills training, will probably pay off. The great American economist J.K.Galbraith once pointed out that, contrary to received wisdom: “It requires no courage nor prescience to predict disaster. Courage is required of the man who, when things are good, says so.”

So let me be bold in the face of the storm and suggest that some things we are already doing we should just keep on doing. And what could be more controversial than that?

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