The Government’s latest initiative, to foster co-operation between schools and lessen the damage caused by competition, is “federation”. Is this just another crackpot Whitehall scheme ? Or might its core idea - that we need formal collaboration between schools - mark the beginning of the end of the quasi-market in secondary education? Allowing parents freely to choose their child’s secondary school may have had benefits but the drawbacks are now all too clear.

The Government has good reasons for wanting schools to help each other. While the best-achieving have limited scope for further improvement in results, their neighbours struggle, especially in cities. British pupils may be among the world’s highest achievers, `as the recent Organisation for Economic Co-operation and Development’s PISA study found. But the achievement gap between social classes remains one of the biggest in the world. Our notorious “long tail of underachievement” threatens the Government’s long-term targets. Who has been disadvantaged by the schools’

market? The disadvantaged.

Ministers seem well aware that, unless schools collaborate, those that are struggling will continue to be left behind. Significantly, the new top-of - the-range “advanced schools” (replacing beacon schools) will have to collaborate with others.

The Government is also seeking volunteers to pilot “federations” that would establish formal links, perhaps even run by a single governing body, (now permitted by the 2002 Education Act). Collaboration has so far been poor. In cities, schools must be encouraged to federate. One condition is vital: targets and league tables must be published only at federation level. Top-scoring schools would then have to help lower-scoring partners to move up the table, giving new hope to the desperate.

The Department for Education and Skills says that federations will “recognise (and share) excellent practice in every institution”, “extend the reach of good leaders” and broaden the curriculum on offer.

One way to do this would be to put the schools under a single, “super-head” taking all the key decisions. But a more likely model is promoted by Tim Brighouse, the new schools commissioner for London (TES, October 4). He wants to create voluntary partnerships, or “collegiates”, with overall leadership or “dean” posts taken by heads in rotation. London schools are uniquely various: they could be grouped, across boroughs if need be, to contain a mixture of popularity, faith, gender or value-added attainment.

Both models, however, miss a key element: the need to tackle the social polarisation that blights many urban schools. There is now much research evidence to show that, while privileged pupils thrive almost anywhere, disadvantaged pupils need a mixed environment. In London at least, this can only be achieved by sorting out the secondary admissions mess.

One way to achieve this is to allow parents to choose a federation rather than an individual school. When allocating pupils within a federation the admissions authority might then take into account a well-founded parental preference, perhaps for a faith-based education, the pupil’s needs and wishes, and society’s requirements, including the need for more balanced intakes. Children’s own rights are currently completely unrepresented; in general, they would prefer simply to transfer with their friends to a local school, rather than be sent long distances to their parents’ favoured choice.

We must contest rhetoric about parental choice, which sounds hollow to Londoners. They know popular schools choose pupils, leaving many parents with no choice, and that some pupils have no school place at the end of Year 6. A guarantee of a federation place might spur middle-class parents to focus on making the most of the huge opportunities within it, rather than forcing their way into popular schools.

This might bring gulps from our more timid policy-makers, fearful of upsetting Daily Mail readers. But such federations would offer a full range of extra-curricular activities. Crucially, each school would contain the critical mass of motivated students that is needed to encourage less favoured pupils to succeed.

One thing is undeniable. London’s secondary admissions system is not working. It takes up too much time and resources, leaves parents dissatisfied and children stressed and facing long bus or tube journeys. It divides secondaries into “haves” and “have-nots”. If Tim Brighouse is to succeed in the capital, the admissions problem must be resolved.

Martin Johnson is an education researcher at the Institute for Public Policy Research. For details of a forthcoming IPPR conference, Schooling in London, contact m.johnson@ippr.org.uk