Why do certain parents abandon their scruples when it comes to paying for their children’s schooling? Peter Wilby chews over a dinner party dilemma

I finally realised that new Labour was - well, nothing like old Labour - when it emerged in 1995 that Tony Blair would send his son to the London Oratory, the poshest of London’s grant-maintained schools.

Labour’s policy at the time was that such schools should be put back firmly under local authority control and all special favours abolished. “Now they’ll have to change their policy,” said a colleague. No, I explained, they would not. Blair would say the Tories had made local authority schools inadequate and inferior and Labour would restore them to their proper glory. In the meantime, parents who deplored the present system were justified in protecting their children from its worst effects. No hypocrisy was involved.

But within a few days, David Blunkett, the shadow education secretary, had started to fudge Labour’s policy. Later, the policy on grammar schools was fudged as well. Hopes that life would become more difficult for fee-charging schools - by, for example, abolishing their charitable status - receded, although Labour ditched the assisted places scheme.

Mr Blair has no difficulty with middle-class parents manipulating the system to get the best for their children. On the contrary, in his view, the system should be designed so they could manipulate away; the state should encourage the aspirational classes.

Adam Swift, a political philosopher, takes the old-fashioned view that the state should act for the community as a whole. On that criterion, private and grammar schools should be abolished. What we call “good” schools - schools that get the best exam results - are in reality the schools that have “good” pupils. Schools and their teachers do make a difference, but nothing like as big a difference as the intake.

Private schools contrive to give themselves a double advantage because they select on income and ability. If creaming off advantaged pupils simply gave them a better education without affecting anyone else, there could be no case for abolishing Eton and Winchester, and to do so would indeed be an act of wanton vandalism. But that, as Swift explains, is not so. The best way to improve the performance of disadvantaged children is to put them in a school with advantaged children, achieving a spread of ability and background. The disadvantaged will then do much better and any detriment to the advantaged will be small.

Therefore, if 7 per cent of families are allowed to opt into private schools - or 20 per cent into grammar schools - the remaining children are deprived of a decent education. By any standards of justice or efficiency, that is a bad deal for society.

Swift disposes of all the arguments commonly used against abolition. To bring state schools up to the standards of the private sector is impossible, he argues: if the latter’s superiority depends on their having the best children, it is a contradiction in terms; and some independent schools have such lavish resources that Britain would be ruined if they were extended to all. Nor, he maintains, should you have a right to choose a private school. You have rights to things that are integral to family life, but paying for your children’s schooling to give them positional advantages isn’t one of them.

So can you embrace Swift’s arguments and still choose a fee-charging school? If you think the wickedness of private education is that it makes state schools inadequate, you are likely to find the local comprehensive inadequate. Then you would not only be unhypocritical in opting out, you’d be morally right.

This is obvious to Swift, but not, unfortunately, to most people, including Tony Blair. And I fear it is not entirely correct. As Swift acknowledges, you are justified in opting out only if your local comprehensive is so inadequate that your child would be seriously damaged by attending it and if you then choose a school that is simply adequate (or a little better) rather than one that opens a gilded route to Oxbridge. On that basis, the Blairs, who lived in the London borough of Islington in 1995, and didn’t go private, are in the clear. But most paying parents (morally perplexed or not) reject comprehensives, which, given all their children’s other advantages, would be good enough for them, and choose schools that offer a degree of exclusivity or resourcing unobtainable in the state sector. Even the Blairs could have followed the example of an earlier generation of middle-class Islington parents, who sent their children to the local comprehensive and worked to improve it.

I am reluctant to criticise Swift because his book is refreshing in its clarity and cogency. But it is a case study for political philosophers, not a guide for parents. Philosophers, while they try to use homely examples - apples, pianos and cricket matches - do not quite live in the real world.

Swift does not use the word “snobbery”. What the middle classes, including the left-leaning, private sector-abolishing middle classes nearly always find, at age 11, if not before, is that they can’t bear their children to mix with the working classes. It is, I suppose, just about possible to favour abolition of fee-charging schools while unhypocritically sending your children to them. But I am reminded of camels and eyes of needles.

Peter Wilby is editor of the New Statesman