We look to Scotland”, said Voltaire, “for all our ideas of civilisation.”

While the Scottish Enlightenment, which spurred such praise, may be long past, its achievements still add lustre to Scotland’s international reputation. Nowhere is this more marked than in the field of education where Scotland’s comprehensive schools and accessible universities are still widely admired.

I discovered this myself when, three years ago, I told London friends that I was moving back to Scotland to work for the First Minister. “Designer move”, said one mother admiringly. She, like many of my friends, was going through the tortuous secondary transfer process in London. In recent years, this has become a military campaign involving scouting schools at least a year before application dates, hiring tutors, practising entry exams and even assiduous church attendance by parents who are committed atheists. It is a brutal, bruising business with many adult friendships going into hibernation as their offspring compete for the limited places in desirable schools.

In that context, moving to Scotland looked like an inspired strategy, rather than the happenstance of grabbing a unique career opportunity once offered. After all, Edinburgh had the holy grail - comprehensive, neighbourhood schools providing excellent state education. My elder son, then just approaching secondary transfer, would be spared the uncertainty and heartache of trying, and perhaps failing, to get into the school he wanted.

And, in part, so it proved. In November 2001, he knew that he was going to Boroughmuir High, while back in Peckham his best friend did not know until August 2002 - days before term started - that he had got into the nearest boys’ school.

On the face of it, my experience is a clear example of the superiority of the Scottish system. There is no doubt that there was an immense benefit for my son in being one of 80 kids transferring together from a local primary school to a high school, particularly as he had only been in Scotland for less than 18 months. In contrast, the three year 6 classes in his South London primary scattered to 32 different secondary schools.

The underlying reality is much more complex. Schools here do have catchment areas, standards are high. Where comparisons can be made, they are above those achieved in England. But, in truth, they are only comprehensive in the narrowest definition of that term - that pupils are almost entirely drawn from the surrounding district. The extraordinary residential, social segregation in Edinburgh - mirrored in our other cities - does all the work of selection. In place of the testing, specialisation and interviewing which are used in London, we have a far more straightforward postcode purchase of state school places.

When I moved back to Edinburgh I returned to South Morningside, partly because it was where I grew up - and it has been nice to meet as parents friends who were at school with me - but mainly because I knew that as a middle-class professional I could afford to pay for the housing which allows me to access excellent state education. And the fierce contest for housing in the area suggests that I am not alone in understanding that fact.

I do not want to argue that our system is worse than, or even as bad as, that currently operating in London. As the leading centre-left think-tank, the Institute for Public Policy Research, pointed out recently, education in London is not working - standards are stalled, provider choice operates rather than consumer choice with schools choosing pupils and parents. There is a real danger of ghetto schools being created.

ut I’m not sure that we have much to be smug about here. For all that we celebrate the meritocratic myth of the lad o’pairts and the democratic intellect, the pattern of postwar Scottish education has been one of expanding opportunities being consumed by a growing middle class.

The proportion of young people from working-class backgrounds getting good Highers and university places has remained static for more than 30 years.

One of the depressing, but unsurprising, discoveries I made on returning to Edinburgh three years ago was that the struggling secondary schools in the 21st century are the same ones that had poor results when I was in school in the 1970s.

This is the dark heart of educational politics north and south of the border - no one, whether new Labour or Scottish Labour, wants to talk about class-based disadvantage. Yet it is the most prominent fact of Scottish political life that the best advice you could give an ambitious working-class child is to get born into a middle-class household.

Being young, Scottish and working class is, by and large, still a ticket to low attainment, lifelong poor health, bad housing and an early grave. None of these challenges is easy to sort, but it would be a start if we could abandon some of the hypocrisy surrounding discussion of them.

Estimates from the United States suggest that to equalise opportunities for black inner city kids with their white suburban peers requires an investment of at least 10 times more in resources. What are the equivalent figures for our nation - and are we any more willing to pay up than our American counterparts?

John McTernan is a former special adviser to the Scottish Executive and chairs a school board.