It’s fair to say that the general election has somewhat overshadowed Justine Greening’s speech a couple of weeks ago about grammar schools and social mobility.

But with the Conservatives sure to seek a mandate to expand selective education in the coming election, the clues contained within the speech about the direction of the government’s thinking are potentially even more significant now than before.

The case for selection must be made to the public; and it’s imperative that it is founded on solid policy-making principles, rather than intangible ideology.

For those keen to see the detail underpinning the promised new generation of grammar schools, Ms Greening’s speech was something of a damp squib. It remains unclear exactly how the government intends to translate its ambition to “make grammar schools engines of academic and social achievement for all pupils”, as set out in its Green Paper, into hard policy.

The much-anticipated White Paper was mentioned only as a side note in the speech, and the election will likely delay its publication. Suggestions of “tutor-proof” entrance tests, and a quota system to ensure places for less well-off pupils, remain ethereal rather than material.

Yet while the speech was short on particulars, Ms Greening’s remarks were far from uninformative.

Noting the shifts in rhetoric and messaging, it is hard to avoid the suspicion that the government knows it is running out of road in its attempts to envisage and articulate how selection can help to bring about a school system which genuinely “works for everyone”.

Dramatic change is needed

We at ResPublica believe this is indeed possible, and that grammar schools can, under a restricted set of circumstances, be the right vehicle to raise the quality of an area’s education provision and deliver real social value to communities as a whole.

Data suggests disadvantaged pupils see most added value from education in a selective institution: in 2015, 92.7 per cent of free school meals pupils in grammar schools achieved five or more GCSEs or equivalent at A*-C grade, only 3.7 percentage points lower than the rate for non-FSM pupils, in the context of a gap of 27 percentage points across all schools.

Situating selective schools in areas with high concentrations of such pupils maximises the number of pupils who can benefit from this effect.

Furthermore, if these were introduced in areas where there are no existing “good” or “outstanding” schools, we believe they could act as a catalyst for long-term cultural change by providing a model of excellence which can influence practice in other local institutions, driving up the quality of the education provided to all pupils in the area.

Incremental changes cannot deliver reform at this scale; if we are to avoid failing a generation of young people in these areas, dramatic change is needed.

This is a strategic approach to selection, acknowledging that it should be treated as an instrument of public policy rather than an ideological tenet.

Ms Greening’s speech, however, signalled a low-key retreat from pledges to make new selective schools “contribute meaningfully to raising outcomes for all pupils in every part of the system”, as the prime minister promised in September, towards more celebratory rhetoric emphasising the number of “ordinary working-class” children who “already attend existing grammar schools”.

The government appears to be losing either its appetite, or its belief in its ability, to design the policy in a way which primarily benefits the less well-off and increases social mobility.

Its aspiration to make grammars “open to all” by “reflecting the choices of local parents and communities” is likely to lead to a re-emergence or expansion of selection in more prosperous areas.

The government needs a bold strategy

This will mainly benefit children from more prosperous backgrounds, who the evidence suggests are more likely to attend selective schools yet who see little added value from them, while actively harming the prospects of the less well-off children who fail to get in.

In more deprived areas, by contrast, there is an opportunity to provide real benefits for disadvantaged pupils who do get in.

As such, while we continue to make the case for the potential benefits of selection, we do not believe the government’s policy is sufficiently well-crafted to deliver these. Government should be detached, not ideologically committed, about selection.

It should regulate its use and approve it only where necessary to achieve the wider aim of securing a balanced system and a good education for every child.

Ms Greening’s speech suggested the government has backed away from this laudable ambition; but the election provides an opportunity to reset the Conservative position.

Rather than the the speech sounding the death knell for a potentially transformative policy, the election offers a platform to iterate a new grammar school model, founded on a whole-area approach to all phases of education, working with primary and non-selective schools for mutual benefit in disadvantaged areas where this is most needed.

This will enable grammar schools to be agents of positive local change in the necessarily limited number of areas where they can perform this role.

This position may please neither the hardcore proponents of selection nor its fierce opponents; yet it is the platform which we challenge the government to be bold enough to put to the country.

Duncan Sim is policy and projects manager at thinktank ResPublica

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