The first question about selective schools is a question about all secondary schools: who decides?  Should central government have the last word, either way?  Or should local authorities, parents, and teachers instead?

The direction of policy under the main parties in recent years is unambiguous.  Gone are the days when a Rab Butler or a Tony Crosland would push for a fixed tripartite or comprehensive system from Westminster and Whitehall.  Inspections, exams, testing – the Department for Education sets a consistent standard for all these (or tries to).  But when it comes to new schools, variety trumps uniformity.  Comprehensives, faith schools, grammars, academies, free schools: welcome to the new mixed system.

Since this is so, the next logical step of the journey is a localist one: to give those councils, teachers and parents an even bigger say.  And if they want more or new selective schools in their area, it follows that this is a decision for them, not for Nicky Morgan or Tristram Hunt at a distant desk in central London.

So the answer to the selective school question turns out to be simple – whatever the effects of selective schools may be on other schools, on children in the areas in which they exist, and on the system as a whole.

However, a simple answer isn’t always the same as an rigorous one, and it is imperative to try to find out what those effects are – for the sake of the development of children and the health of the system itself.  Do areas with selective schools produce better or worse results for all their pupils than non-selective area? Does a selective system work better than a non-selective one? These questions have been at the heart of the debate on grammar schools that we’ve hosted on ConservativeHome this week.

There is no shortage of facts and figures from either side of the argument, though my sense is that the opponents of selection are pushing theirs in more depth.  But the statistics are ultimately inconclusive, because they are measuring what was or is, not what could be.

Studies of the pre-comprehensive age gaze back to a vanished world, in which the eleven plus decided the educational fate of most of the country’s children.  Work patterns and family life were very different, and access to University far more limited.   Studies of the post-comprehensive one (that’s to say, of the present, with its more varied school provision) look around at a country in which selection is confined to a small minority of areas that by and large use one type of test – Buckinghamshire, Kent, Lincolnshire and a few smaller local authorities that have kept their grammar schools and the eleven plus.  This is a questionable basis for drawing conclusions about, say, what would happen in schools that selected – but by a different method.

In a sense, then, the entrenched positions at either end of the debate are talking past each other.  Both assume that at its core lies a choice about whether to return to a system based on the eleven plus.  But there is no intrinsic reason why this should be so. Indeed, the eleven plus is arguably the Achilles Heel of the selective system, since its neutrality between children from different backgrounds is questionable, and it is often premature to make a major decision about a child’s educational future at eleven.

This helps to explain why Graham Brady has praised the “creative thinking of Conservatives in Wales, who “are not talking about entrance exams at 11, but a process leading to selection at 14 based on the preferences of the child and the parents”.  Damian Green has stressed the importance of improving the performance of primary schools, so that pupils from more deprived backgrounds are at as little disadvantage as possible when selection takes place.

Both are pushing the best reason for those local authorities, teachers and parents to consider new selective schools – namely, to give poor children life chances they would otherwise not get.  (And at a time when some argue that social mobility has stalled, and more secondaries have been found to be failing.)

I am not at all sure that many local authorities would want to pursue selection were the Department of Education to ease restrictions on it, at least at present.  As Green wrote on this site earlier this week, the selection debate is haunted by “our perennial agonising about class”.  Whatever the facts may be about the performance of non-selective schools in selective areas, folk memories of the failures of the tripartite system linger.  The technical schools that Butler envisaged never happened.  Too many secondary moderns wfailed.  No wonder Crosland – and yes, Margaret Thatcher – were able to push through so much comprehensivisation.  There was simply too little parental resistance to stop them.   And no wonder Michael Gove took the low road of mixed-ability academies rather than the high one of selective grammars in order to aid poorer children.

In short, the politics of selection are perilous for a party battered by claims that is “the party for the rich”.  Were restrictions on it to be eased, the Labour script would be predictable: “This is a lurch to the right by the Tories.  They want to help posh kids in the shires. They just don’t care about working people.”

However, this attack line is open to counter-attack.  The Sutton Trust has found that only 17 out of the 100 most socially selective state schools are grammar schools.  Some of those that aren’t are in effect offering selection by house price instead of selection by ability.  Well-heeled Labour politicians can afford to send their children to good comprehensives in plush areas.  Poorer parents dependent on grammars can’t.

But in any event, a future Conservative Government might take a leaf out of Dominic Raab’s Meritocrats Manifesto, and allow new selective schools to be established first in deprived areas with poorly-performing schools.  The catchments for these might be drawn wide, as Green suggests, so that they can take pupils from a city or county.

He also floats dropping the grammar label altogether.  This might make these new schools easier to popularise, or reflect the fact that they wouldn’t necessarily use the eleven plus – or both.  Certainly, the lab would be less important than the fact.  I wouldn’t care if such new selective schools were called College Schools or Curriculum Schools or Meritocracy Schools or Kim Kardashian Schools for that matter, as long as they worked.  I will stick with Meritocracy Schools until someone comes up with something better (which doubtless won’t take long).

At its core, the case for selective schools isn’t hard to grasp, which is doubtless why some other countries are less inhibited about having them than we are.  Some schools select their students for different sets or streams after they’ve been admitted, and select by aptitude for students before they are – though the Labour Ministers who invented specialist schools fought very shy of the “S” word.  There are specialist music schools and language schools and sports schools.  It would scarcely be a great leap of principle to create specialist academic schools too.

As I say, I suspect that academies will offer the most popular way forward for academically-strong pupils – but let’s find out. And at the same time, we can turn to a topic which tends to exercise the centre-right less, but should preoccupy it more: namely, providing better education and training for students who are not academically strong.