An internal frontier runs through Britain. People cross it under cover, shamefacedly, by slipping cash to the guards. If they are caught, they protest that they were forced across. To say they had strayed over inadvertently would be risible. The frontier is clearly marked: "You are now leaving the state sector of education." And it is not as if you could fail to see how different things are on the other side.
Education in Britain is a Berlin where the Wall is so well established it is sprouting weeds. Any attempt to open things up - as I have found while promoting the return to the state sector of the 120 former direct grant schools obliged to go independent in the Seventies - makes people strangely uneasy. For some, segregation holds illicit attractions. For others, our two-nation education system is an insurmountable reality, the division too deeply embedded - in our culture, in our politics, in our sclerotic British bones - to be changed.
The greater the evidence that some ex-direct grant schools might actually be interested in change - not just Manchester Grammar, who have said so publicly, but some 70 others who have written to me - the greater the unease. Here are enlightened and experienced heads who never wanted to close their schools to ordinary folk in the first place, and who in certain circumstances might be interested in re-opening them to all the talents. How can you decently tell them to shove off?
For conventional thinkers of the left or the right, it is all deeply disorientating. Our educational Cold War has become a way of life. They have made thunderous speeches on the subject from both sides of the Wall. They know the speeches by heart and are damned if they are going to learn any others. For Conservatives especially, some of those speeches may need to be amended. We have spent two decades denouncing Labour for driving the old direct-grant schools into the private sector. If we pretend to go deaf when they show interest in coming back, we could look silly.
The Government protests that reintegrating them would be expensive, declining to investigate the possibility of redeploying money from the assisted places scheme (APS) to that end, or of charging fees to the better off, as was done previously. The APS is a great conscience-warmer for Conservatives. But there is a big difference between handing down scholarships and opening up first-rate schools to all, as of right.
It is not true that all the APS money goes to former Lloyd's names, distressed gentlefolk and the like. Only some. The scheme does indeed pluck a few souls from the streets, and in Dickensian times it would have looked positively enlightened. It is just that in shoring up private schools, the APS is shoring up the very divisions that are at the root of the problem.
Our educational Wall is buttressed by the left as well. On the face of it, the notion of 120 of the best private schools voluntarily re-joining the state sector ought to be attractive to Labour - especially since the former direct-grant schools had links with local councils. It could snatch the baton of educational innovation from Tory hands. It could overcome Labour's problem with its commitment to abolish the APS outright - destroying the single (admittedly defective) bridge while having nothing to put in its place is hardly constructive politics.
It could reinvigorate the state sector by providing much-needed pinnacles of achievement, and give the private sector a little more of the competition it claims to believe in. For a party seeking to cast off its image of drab, downwards conformity, it would be an imaginative gesture. Positive thinking about state and private education would be a natural next step after Tony Blair's recent triumphs: a Clause IV of the mind. But it could only be done at the cost of abandoning much-cherished prejudices.
None of the schools that have written to me would contemplate coming back if it meant sacrificing its independence or academic standards. As I understand it, Labour's position on selection is: selection by class and by cash, fine; by ability or aptitude, never! Which means, in effect, that high academic standards in the independent sector can be tolerated so long as they are not available to the child in the street. A dog-in- the-manger policy if ever I heard one.
If Labour die-hards re-read their Tawney, they would discover that educational egalitarianism is a relatively recent and uniformly disastrous invention of the left. Is Labour doomed to shore up its side of the Wall indefinitely by refusing any form of selection?
There are interesting signals. Mr Blair responded to a letter that I wrote to both him and the Prime Minister by asking to see me. We had a grown-up conversation, during which I expressed genuine puzzlement as to how Labour would deal with the private sector if it was elected. Punishing it would be pointless, unless the aim is to destroy excellent schools, and national assets. I am interested to see that the latest Labour document on education says nothing about private schools.
There is heated agreement in Britain that, in the world as it is going to be, education will be our main strategic asset. But the moment you touch on the nub of the problem - our two-nation system - otherwise reasonable people will tell bare-faced untruths. Conservatives pretend that private education is open to everyone, as a matter of choice, which is an economic untruth and Labour pretends that the only reason independent schools outshine state schools so persistently is that they are better financed, which is an educational untruth.
Obviously, useful things have been achieved by some of the Government's reforms. Yet overall, Britain seems destined to remain as it is: a country of over-promoted mediocrity and underused talent. If nothing is done to chip away at the Wall, both Labour and the Conservatives can forget their promises to equal European standards. No country where the entire apex of society opts for private education has a high-quality state sector.
The impetus for serious reform will never be there, because the top seven per cent - by and large the movers and shakers of society - have no personal interest. Money alone will not buy fundamental improvement: you can have wall-to-wall facilities and one-to-one teaching and still produce middling results, should you happen to have the wrong teaching philosophy. There will never be a serious assault on the low expectations denounced by David Blunkett in a speech at Ruskin College recently until the movers and shakers move and shake as never before.
At present they are all mouth. They deplore the plight of state schools, issue indignant calls for more cash, then skulk off across the frontier to buy places for their children in the schools they went to themselves, and where they fully expect their grandchildren's grandchildren to go. They know perfectly well that cash is only half the problem, but their consciences are assuaged, which is all that matters.
Meanwhile, the purveyors of low expectations carry on, content in their wretched way with their culture of resentment. So everyone is happy. Sometimes one has the impression that, disastrous as it is for the country, secretly we have grown to love our Wall.
The writer is Conservative MP for Buckingham.