Rarely have experts in the field of education - classroom teachers, school leaders, academics - been so united: we do not want to see new grammar schools opened. There is widespread agreement that a selective system sidelines poor children, and benefits those who pass the 11-plus at the expense of those who fail it.

And yet the majority of the public, and many Tory MPs, support new grammar schools.

Should we do more to research and present evidence on the impact of academic selection in the hope that they can be persuaded to change their minds? I wish this were possible - I have hung my entire career on trying to shape education policy through empirical evidence. But this debate feels emotional, not evidential.

And so at the national ResearchEd conference in London tomorrow, teacher Jonathan Porter, former government adviser Sam Freedman, TES head of content Ed Dorrell and I will explore how the general public and politicians can be persuaded to think again about opening new grammar schools.

I think what we will say may challenge the teachers in the audience. How is it that so many middle-aged people who themselves passed through the comprehensive system now express support for a return to selection? They may not fully understand what they are voting for when they vote for selection, but they certainly know what they are rejecting.

I suspect that today’s debate about grammar schools is not really about academic selection but is instead a proxy for the frustration many feel about the shortcomings of the comprehensive they or their children have experienced.

So, rather than crunch more and more data to show how damaging selection is for the majority, perhaps it is time to put comprehensive education in the dock and ask why many who experienced it now reject it for their children and grandchildren.

Jonathan Porter recently wrote for the Conservative Education Society of “the grain of truth” at the heart of the argument in favour of grammars - that people who went through the comprehensive school system know that there were systemic failings. The dominant progressive culture in education did not promote an academic curriculum with the highest standards, especially for the most able. Classrooms infused with learning-by-doing, group work and collaborative learning projects promised so much, and yet, for the students, in delivery sometimes drifted into chaos and confusion about purpose. And as the pendulum swung away from a view that strict discipline was best, many remember their own school years as a time when the behaviour of a minority of children inhibited the learning experiences of the majority.

It is possible that rose-tinted views about grammar schools are an expression of the exasperation of Tory MPs and the public with the progressive teaching movement.

‘We’re moving in the right direction’

I actually think that the education system has been slowly moving in the right direction for the past 20 years. The Labour government took comprehensive schooling by the scruff of the neck and pushed it towards being a system where excellence in results was lauded, the importance of literacy and numeracy was emphasised, and there was recognition that the gifted and talented may need specific provision. The Coalition and now Conservative government has promoted an academic curriculum for all to age 16 and allowed more radical experimentation around “no-excuses” discipline and direct instruction teaching methods at free schools.

Alongside all this, we are currently making such great progress in understanding the brain, how we learn and how we recall information that we have the potential to make huge leaps in the efficiency of the teaching and learning process.

As a result of these reforms and innovations we now have some outstanding all-ability schools, quite unlike the ones that many voters experienced. We need to find a way to show voters what comprehensive education at its best can look like. And we need to develop the means of disseminating and replicating best practice to ensure more pupils can benefit from an outstanding education.

I think we can persuade doubters that all-ability schools can work, by arguing that they can provide a grammar school education for all.

But we can only do this if we actually believe the direction of travel in education policy is right. And here is where the tension lies. I think most would agree that the teaching profession is still more progressive in its ideals and methods than those in many sections of the public, and in the Tory party, would like. It is not that progressive ideals are right or wrong, but they do present a value judgement about what is best for children - a value judgement that has dominated for so long because teachers believed that they should get to choose what sort of education system we have.

This has been changing. In recent years we have been moving towards a system where it is recognised that teachers should not get to decide how schooling works - and it is absolutely right that it is the public, and their elected representatives, who do get to make this decision.

In my view, the public are reasonably agnostic about the form schools take, but care deeply about the type of education that their children receive.

So the debate we need to have should be about how the education that children receive in comprehensive schools can be brought more in line with what the public want.

If someone told you that in order to save the comprehensive education system you had a deliver an academic curriculum using traditional teaching methods, would you do it?

Rebecca Allen is director of research organisation Education Datalab @edudatalab

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