school exam
Admissions for grammar schools are decided by the 11-plus examGetty

The next few years will act like a short, sharp dip in ice-cold water for anyone who still foolishly clings to the idea that New Labour and the Conservative Party were part of the same project. This is a lazy generalisation that ought to have died off years ago. And yet it is flourishing – indeed, the Labour Party is now controlled and directed by those who view the New Labour years as in some sense a shameful aberration from 'pure' socialist doctrine.

Yet while Labour's dominant faction denounces everyone to the right of the late Tony Benn as 'Tory-lite', actual Tories are busy straining every sinew to uproot some of the most significant New Labour policies. While Jeremy Corbyn's Labour Party gets increasingly drunk on ideological fervour, the Conservatives are wielding power unencumbered by meaningful opposition.

This week, Conservative Voice, a Tory activist group set up by David Davis and disgraced former defence secretary Liam Fox in 2012, will launch a campaign to overturn a 1998 law introduced by Tony Blair blocking the creation of new grammar schools. They plan to get rid of Blair's ban and seek the 'return of grammar schools throughout the country', as the founder of Conservative Voice Dan Porter put it last week. More than 100 Tory MPs are expected to back this push for a new generation of grammar schools. New education secretary Justine Greening has said that she is 'open- minded' about allowing new grammar schools in England.

Grammar schools are one of the most enduring educational myths. The romantic penumbra surrounding them is bound up with the idea of a golden age of social mobility after the second World War. In popular myth, collapsing social mobility in the present is contrasted with an era when grammar schools readied the way for working class kids to move up into the professions and, in some cases, beyond and into the elite itself.

Yet along with the notion of meritocratic grammars, the idea of a golden age of social mobility after the war is largely mythical. Or at least, most social mobility came about as a result of wider structural changes in the economy rather than any specific education policy. The influential Nuffield Mobility Study, carried out from 1968 to 1971, found that while there was a significant degree of social mobility in post-war Britain, it was mainly due to the expansion of middle class and professional occupations. In other words, a greater number of working class kids got professional jobs than in the past because there was more room at the top.

In popular myth, collapsing social mobility in the present is contrasted with an era when grammar schools readied the way for working class kids to move up into the professions and, in some cases, beyond and into the elite itself.

Part of the attraction of the old system – Labour and Conservative governments got rid of most grammar schools in the 60s and 70s – undoubtedly feeds on the knowledge that stark inequalities persist in comprehensive schooling. Despite the formal abolition of selection, in reality it persists – selection by wealth has very often replaced selection by ability. According to a recent survey of 1,100 parents of school-age children, parents are willing to pay 18 per cent more for a property near their preferred school – the equivalent of £32,000 on the average property price of nearly £180,000 in England, Wales and Scotland. In London, the premium is £77,000 on a house costing £474,000. Fees for ultra-exclusive private schools range from £3,000 to £27,000 per annum.

Yet aside from the fact that selection at age 11, even if it could work perfectly, is a fundamentally conservative-meritocratic idea – excellence is associated with plucking a small number of talented pupils from the mass, with the majority typically condemned to drudgery – there is very little evidence that grammar education works even on its own terms. This is why believers in the meritocratic ideal, such as Tony Blair, did everything they could to prevent the opening of more grammar schools.

You don't need to go back and delve into the many stories of highly intelligent people who failed the 11-plus to see that the romanticism surrounding grammar schools is misplaced (though examples of this are tragically common). You can instead simply look at the grammar schools still in existence today. Educational performance for poorer pupils in areas where selection persists is significantly worse than for their equivalents in comprehensive areas.

Don't be fooled by the beguiling language of social mobility and meritocracy that will no doubt come in punchy soundbites from the members of Conservative Voice this week.

It is easy to forget that selection at age 11 still exists in 36 local authorities. A recent study of Buckinghamshire, a county with a wholly selective school system, found that private school pupils were two and a half times more likely to pass the 11-plus than state school pupils. The pass rate for pupils for children on free school meals was just one-eighth of the average. The discrepancy between wealthy pupils and the rest occurred in spite of the introduction of supposedly 'tutor-proof' testing in 2013. The rich were still able to pay private tutors to beat the 11-plus.

Children from poor families are simply not getting into grammar schools. A recent study for the Sutton Trust found that just three percent of those attending existing grammar schools were entitled to free school meals. Meanwhile almost 13 percent of entrants came from the independent sector, largely made up of fee-paying preparatory schools. According to the IFS, deprived children are significantly less likely to get into a grammar school than the most privileged.

The inequality generated by grammars then feeds into the world of work. Areas that have retained selective education have a bigger average wage gap between high and low earners. The highest earners from grammar school areas tend to be better off than top earners born in comparable comprehensive authorities.

Don't be fooled by the beguiling language of social mobility and meritocracy that will no doubt come in punchy soundbites from the members of Conservative Voice this week. Grammar schools may benefit the 20 to 25 percent of pupils who attend them, but education for the rest invariably suffers as a result. It is bad news for poorer kids if grammar schools really are back on the agenda