Ever since the 2001 Green Paper Schools building on success, and subsequent talk of ladders and escalators, many people have felt uncertain about the Government’s vision for secondary education.

Is the aim to develop a system of secondary schools that are all of equally high quality? Or is it to create a hierarchy in which some will always be better than the rest? Some policies seem to lead in one direction and some in the other.

Take, for example, the new policy to encourage expansion of popular and successful schools, irrespective of surplus places in other less popular ones. It is obviously regarded as an important proposal, enough to have been included in the Prime Minister’s recent lecture to the Fabian Society on Progressive politics maturing.

A few weeks ago it was announced that pound;37 million had been allocated to local education authorities for 2003-4 alone to support its implementation. And the Government has undertaken to provide a capital lump sum of pound;500,000 (or pound;400,000 if the school has no sixth-form) for accommodation when expansion takes place.

This means a commitment of about pound;75m if one school in every LEA expands. And that is not all. The lump sum is estimated to be about 25 per cent of the likely costs.

The Department for Education and Skills’s guidance states that LEAs will usually be expected to fund the balance of investment. So we are talking about pound;337m from the public purse to expand one school per authority (there may, of course, be more). So, why are millions to be spent on places that are not needed? The rationale is set out in a statement by school standards minister David Miliband:

“We’re determined to give more pupils and parents the chance to attend high-quality schools, therefore we are making it easier for popular schools to expand.”

There is no definition of a popular and successful school but it appears to be an oversubscribed one which offers a high-quality education - which, by implication, other schools do not. The proposal is presented as “a win-win situation for parents, pupils and schools”. Who could possibly object to that?

Well, for a start, there are the parents and pupils at the school half a mile away from the expanding one, a school which is less popular but improving rapidly. This is thanks to the superhuman efforts of all concerned, and to support from other central government initiatives.

If the resources about to be ploughed into the expansion were spent at this school, it could help to secure its rising achievement and enhance its public image. In another year or two, parents in this area might have two high-quality schools to choose between and far more children would have the chance to attend a high-quality school.

Instead, the expanding school - being currently the more prestigious and possibly one that chooses its pupils carefully - may siphon off some of those children and parents who could help its neighbour build a culture of high aspiration, as it is striving to do.

Equally damaging, pupil numbers at the latter will almost certainly fall, resulting in budget cuts and staff losses. Some initiatives to raise achievement may have to be abandoned. Morale will drop. The momentum for improvement, which the Government has helped to create, may be stalled.

During the past year, I visited nearly 30 secondary schools for our research project on pupil mobility. I interviewed a wide range of people and studied a mountain of inspection reports.

As a result, I have no doubt that some of the Government’s strategies since 1997, and the funding that has backed them, have brought about real and widespread improvements in city schools.

Many which are neither oversubscribed nor top of the tables are quietly getting on with the business of trying to raise standards and enable better outcomes for their particular pupils - who include children others have failed.

I fear that strategies such as expanding popular schools may undermine their good work. If the aim is to develop a system in which all schools are of equally high quality, and I hope it is, then it seems logical to focus finite resources on bringing the weaker schools up to the standard of the best and supporting those which face the greatest difficulties. Already there is concern that successful initiatives to tackle disadvantage may founder when time-limited funding expires.

Government guidance indicates that applications for expansion should be approved unless it will have a damaging effect on standards overall in the area. I do not know how that will be judged or whose views will carry weight. I just hope that the voices of those who expect to win do not drown out those who will lose lose.

Dr Janet Dobson is a senior research fellow at the migration research unit, University College London. She is currently carrying our research, funded by the Nuffield Foundation, on pupil mobility in secondary schools.

janet.dobson@ucl.ac.uk