The Government faces a profoundly damaging back-bench rebellion over the forthcoming education Bill. Yet the squabbles and wrangling will have been baffling to the public, and will have left many parents and governors wondering what on earth Labour stands for.

Rebels accuse the Government of preparing to sell out disadvantaged children. Ministers retort that good schools must have more freedom and parents must have more choice. So what is the real bone of contention, and is there a way forward that prioritises the interest of pupils over political point scoring?

Labour needs to be clearer about its aims for schools. Raising standards of education across the board will certainly continue to be a priority. But a progressive party must also put tackling educational inequality at the heart of its vision, and do so in a binding way rather than simply asserting its importance in ministerial speeches.

Next month, the final report of the two-year Fabian Commission on Life Chances and Child Poverty, chaired by Lord Victor Adebowale, will propose how to do this in a way that should help Labour rebels and modernisers make common cause.

The current dispute focuses on admissions rules and school governance structures. But for many potential rebels the key issue is educational inequality.

Children from different backgrounds face very different chances of achieving good results at school. Those from professional families are more than twice as likely to get five good GCSEs as those whose parents do routine work. As the proportion of low income children in a school goes up, average results go down.

Children from some ethnic groups do particularly badly, with only one in four black Caribbean boys achieving five good GCSEs in 2002. Even more worryingly, recent evidence from the Department for Education and Skills shows that the gap in attainment between affluent and low-income pupils has failed to narrow since 1998.

The schools system is simply not focused on these problems. Instead it is concerned principally with two other important objectives: driving up average results and ensuring that no school falls below minimum standards.

This is what the DfES has said it will do in its public service agreements with the Treasury, and this is what the audit and inspection regime makes schools and LEAs do.

The Fabian Commission will thus propose that the Government should in addition develop inequality targets for the schools system in the run up to the 2007 comprehensive spending review. Inequality targets would commit the DfES explicitly to narrowing the gap in attainment between pupils of different backgrounds.

This might mean, for example, introducing a target to narrow the gap in the average test results for 11-year-olds between those pupils who receive free school meals and the rest.

The impact would cascade down through the schools funding system, into school governance and admissions arrangements, into classroom practices and be reflected in the audit and inspection system. It would not have to mean “levelling down”: targets already exist to narrow key inequalities in health and employment rates, and can easily be framed in terms of levelling up.

Such a move would be extremely helpful to the Government. Those potentially rebellious MPs who are genuinely motivated by a concern for disadvantaged pupils would have their fears addressed directly. Those who remained recalcitrant would be vulnerable to accusations of bloody-mindedness.

It would also help to avoid the trap that has been set by Conservative leader David Cameron. He wants both to divide Labour and to claim that his education policy is simply a bolder, more radical version of Tony Blair’s.

Putting inequality at the heart of schools policy would both unite Labour and establish a clear dividing line between a political party that really cares about social justice and one that wants to be seen to care.

Most importantly, a commitment to tackle educational inequality would be the best thing for those whom the system currently fails: those who just happen to be born into poverty, or the wrong area, or the wrong family. The Education Secretary, Ruth Kelly, has repeatedly said she intends the proposed school reforms to serve poorer pupils above all others. Her problem is that not everyone in her own party believes her, so she needs to offer a binding commitment.

Simply raising the stakes by claiming the reforms are a test of Labour’s modernising zeal is not enough. Sometimes government needs to be clear about its objectives. Now is the time to put inequality back at the heart of education policy.

Richard Brooks is research director of the Fabian Society