Sevenoaks in Kent, a quiet, affluent commuter town, is the most unlikely site for a teeming political drama. But as the county – and the country – waits for Nicky Morgan to make a final decision on whether to open the first “satellite” grammar school in 50 years, the profound political implications, either way, are beginning to sink in.

The original proposal, for a new co-educational annexe to the Weald of Kent girls’ grammar school in Tonbridge, a full 10 miles away, was rejected by Michael Gove in 2013 and a revised single-sex proposal submitted in November 2014. No one was surprised that the Conservative party fudged the issue in the runup to the general election. But nearly four months on, with no decision forthcoming, there is impatience on both sides, although Roger Gough, cabinet member for education at Kent county council, which is backing the plan, declares himself “hopeful”.

A government insider says: “The department knows it’s not watertight legally. They know it’s going to be subject to judicial review. My soundings suggest that they think they have, say, a 60% chance of winning. Essentially the decision is political.”

If the annexe is approved, it will open the floodgates to similar expansion plans from grammars from around the country. It will also mark a significant retreat from the Gove years, when there was a strong commitment to the principle of non-selective education and rejection of old-style Tory claims that grammar schools promote social mobility.

Gove’s departure, the regrouping of some backbench Tory MPs in defence of grammar education, and the fact that local MP Michael Fallon is in the cabinet, have shifted the balance of power within the party. It’s possible, says one policy expert, that a “few new grammars” are to be offered as a sop to rightwing backbenchers in the long-rumbling row over the European referendum. “Six months ago I’d have said that Gove settled the question of the grammars inside the Tory party and it wouldn’t come back. I was wrong”. However, if Morgan stays firm and rejects the proposal, it will “probably settle the question of the grammars for a generation. The government will make noises about legislation to allow new grammars but it will probably be like foxhunting. It will never happen.”

[wp-svg-icons icon=”camera-3″ wrap=”i”]  Mary Boyle, above, head of Knole academy, Sevenoaks, says: ‘An annexe is an outbuilding or a shed on the school property. It’s not a spanking brand new building 10 miles away.’ Photograph: Martin Godwin for the Guardian

Establishing a new selective school is prohibited under an act passed by Labour in 1998. The satellite proposal has to prove it “is a genuine continuance of the same school”. According to internal Department for Education guidance, this means it must answer such questions as whether will there be movement of pupils between – and staff employed on – both sites. “The more integrated, the more likely the changes can considered to be an expansion.”

However, David Wolfe QC, an expert in education law, believes that as Weald of Kent is an academy, the legal decision is not affected by the 1998 act.

Gough argues the proposed school is genuinely an annexe. “Weald of Kent already gets a lot of girls from Sevenoaks.” But for Mary Boyle, head of Knole academy, one of two all-ability schools in Sevenoaks, “an annexe is an outbuilding or a shed on the school property. It’s not a spanking brand new building 10 miles away”.

There are two main routes from the Weald to the proposed annexe: one along winding roads that go through the shopping centre of Sevenoaks, the other along the busy A21. According to Boyle, “it’s a 20-minute journey at best and more likely 40 minutes or more, given horrendous traffic. I don’t see how anyone could manage a school with that commuting challenge. It would involve considerable additional staff time – at a time of shrinking educational budgets.”

There are differing opinions in Kent as to who is the driving force behind the annexe. Some believe the plan was initiated and orchestrated by leading Tory councillors, but Gough is adamant it began with a parental petition. Certainly, in recent years the campaign has been publicly led by parents Andrew and Sarah Shilling.

Both the Shillings are beneficiaries of Kent’s grammar school system and the first in their families to go to university. Speaking at a debate at the Cambridge Unionin February, Andrew Shilling made the case for the return of selective schooling nationwide, describing the grammars as “a popular and acceptable part of Kent life”. Pointing to Kent’s relative success in the national league tables, in which the county performs above average, he argued that children are now rejected at 11 more kindly – by email, not letter – and that secondary moderns are much better resourced than in the past, with the local school boasting “gleaming new buildings that offer a hospitality suite and dance studio”.

But this is not a fair picture of the aims, achievements or ambitions of Sevenoaks’ two non-selective schools: Knole academy and Trinity free school, which, if the decision is a yes, will share a site with the new school. Boyle says: “We have striven to become an all-ability school and have established a grammar-school stream. In year 7, 8 and 9 we are truly all-ability. And we are co-ed. If the annexe goes ahead, we would lose all the more able girls.”

Boyle believes a new grammar school would also “lead to overcapacity in the area and falling rolls could affect whichever is the least popular school.”

Amanda Manuel is a founder member of Sevenoaks ACE, a group formed to develop a local educational plan that meets the needs of all parents in the area. In 2011, before the council backed plans for the new grammar, the group carried out a survey, getting replies from more than 900 families, representing more than 1,400 school-age children.

“While there was support for grammars, 57% of those polled would support a new non-selective school providing it taught in ability groupings,” says Manuel. “A significant majority also said that a co-educational school was needed.”  Manuel speaks highly of Knole academy, which she says “has won a lot of support locally and has gone from strength to strength.”

Rebecca Allen, of Education Datalab, an independent research team, says all the evidence indicates that “while grammar education clearly serves high-attaining children, it also raises very difficult questions”. She sees no point in comparing neighbouring authorities, comprehensive or selective, because, with so much cross-county traffic, the systems are porous. “Latest figures show that fewer than 80% of children in selective schools are in a Kent state primary; 7% came from another county, and that means probably 13% were in the independent sector,” she says. The tuition industry is another distorting element in the picture.

Allen disputes the well-worn claim that grammars benefit the bright, poor child, an argument confirmed by figures for those eligible for pupil premium in and around the Sevenoaks/Tonbridge area in 2014. Knole academy, for example, takes 21% of children eligible for the pupil premium; nearby grammar schools take 3%, 1% and 4% respectively.

According to Nick Kennard, of the Comprehensive Future campaign group, who lives in Sevenoaks: “People are not being alerted to the serious and negative consequences of a system that rejects the majority of children and segregates them into different schools. There is just so little information, a real lack of debate locally about the benefits of phasing out selection. The status quo is a powerful force and the national media have largely moved on from a debate that was had and won almost half a century ago, leaving the small number of areas in which selection remains largely forgotten.”

Plenty in Kent speak in private of their dislike of the social segregation, snobbery and depression of standards that such a divisive system engenders. But in practice, selection implicates just about everybody in the county: primary and secondary heads, children and parents. According to one mother: “It utterly dominates everything. From about year 3 or 4, the reality hits home. It permeates all conversations and the children’s relationships with each other. By the time you understand the system, it may be too late for your child.”

This piece was first published in the Guardian on September 8th 2015