WHEN I started teaching in 1963, I joined the staff of a small independent school in Devon - and my friends told me I was mad. A Labour government, they said, would abolish such anachronisms, and I would be quickly out of a job. Thirty-nine years later I am out of a job but having, more by accident than by design, taught in independent schools for my entire career, and having retired rather than had my job axed as a result of Government interference.

For many years I have yearned for the gap between the independent and state sectors to close or even disappear. But, while their opponents have frequently predicted the demise of independent schools, over the past 40 years these schools have flourished rather than withered, and most are in a healthy state at the start of the 21st century.

Whether they will be as strong at the end of the century, or even in 2063, not even the most audacious prophet would dare to predict. After all, parents who are contemplating a day school education for their offspring currently face a bill of about pound;64,000 per child. When a similar product can be “purchased” for nothing, there must be something about these schools which is so attractive to parents. In Edinburgh, a quarter of all secondary pupils attend an independent school.

One of the most important factors which has resulted in their increased appeal is their responsiveness to parents. Twenty years ago most independent schools adopted a pretty lofty attitude; now they hold frequent parents’ evenings, bombard parents with questionnaires and market themselves with a professionalism unimaginable even 10 years ago.

Parents pay their fees direct to the school, and expect value for money. Schools that failed over the past 10 years often did so because they ignored what parents - and pupils - wanted. Some heads and governors have resented the ways schools have become more businesslike in their approach, but they continue to do so at their peril.

The independent schools have also gone a long way to broadening their social appeal. Gone are the days when they were only for the children of the wealthy - every day school has pupils whose parents both work full-time and scrimp and save to be able to afford what they see as the best education for their children. And since the demise of the assisted places scheme, many schools have established their own schemes so bright youngsters from less privileged backgrounds can attend.

But there must be other factors which result in so many parents sacrificing so much to educate their children privately. True, for some it is a social obligation - they want their children to mix with children from similar backgrounds. But for the vast majority the reasons are very different. The high level of expectation at independent schools is one. I often asked pupils who joined my school halfway through their secondary education how the school differed from their previous one. Almost invariably the answer was the level of expectations of all pupils.

The extracurricular activities offered in abundance by independent schools are another factor. I can think of many former pupils from the school where I was head whose careers have stemmed from their participation in these activities, ranging from politics (Sir Malcolm Rifkind) to music (Donald Runnicles) to sport (Gavin Hastings). Scottish education suffered a grievous blow in 1986 when teachers in the state sector withdrew their support for such activities, and in many schools they have not fully recovered.

Academic success, of course, is also a factor, although opponents are sceptical of the claim because such schools are academically and socially selective. Of course, they say, these schools should produce better results. But how much better? The percentage of pupils passing three Highers in state schools in Scotland is only 23 per cent, woefully short of that in the independent sector in Scotland. Such a gap cannot be explained by social and academic selection alone. And many independent schools “select” at nursery level, where academic assessment is impossible, or at P1, where it is an extremely inexact science.

espite all this, I am not convinced that the independent sector will survive the 21st century unless it can co-operate more closely with the state sector. This may seem a contradictory statement - after all, if the two sectors come closer together, why pay such extortionate fees? The answer lies in standing the question on its head - can the state sector survive as it is without adopting some of the methods of the independent sector?

Parents of all backgrounds are going to demand more and more of their schools. Political dogma has clouded this issue since the abolition of the grammar school. But there are chinks of light appearing, and private finance is being seen by all major political parties as a way of closing the gap between people’s expectations and the Government’s ability to deliver.

My vision of the future is of a dogma-free environment for education, where the independent and state schools steadily come closer together, to the benefit of both. There are models which can be studied - notably in Australia and New Zealand, and even surprisingly in post-apartheid South Africa and in communist China.

There will doubtless be many difficulties, but none that cannot be overcome if the political will is there. In the long run this would be to the benefit of all our schools, of all our children, and ultimately, of our entire nation.

Frank Gerstenberg is the former principal of George Watson’s College in Edinburgh.