John Glen is PPS to Philip Hammond, and is MP for Salisbury.

Like all Conservatives I share a deep conviction in the transformational role a high quality education can play in changing an individual’s life chances. My parents both left school at 16: my mother to take an apprenticeship in hairdressing, my father to take a vocational qualification in horticulture on day release in order to become a nurseryman. But on the back of the Thatcher reforms of the 1980s, they developed a micro-business, and their first objective was to enable their children to receive a good education which allowed us to be the first in our family to go to university.

It’s because of the power of education to change lives that the grammar school debate – in which Ministers are now apparently joined – matters so much. Lots of government policy can affect us on one or two major occasions in our lives, but a good education can lay the foundations for personal economic security and freedom from reliance on the state for a lifetime.

The political issues surrounding grammar schools are many and complex, and go back a long way: accusations of ‘harking back’ and of postcode lotteries on the one hand, and a call to power up more proven engines of social mobility on the other. But the core policy issue is actually very simple: does academic selection work?

Given the increasing acceptance of streaming (not just setting – rather, an across-the-board separation in classes by ability) within non-selective schools, even the critics of grammar schools seem to accept the principle of teaching children with similar ability ranges is effective – for children at all points of development. Just as the more able are stretched further, so the less able can have more time devoted to overcoming their learning challenges at a particular season of their development.

In which case, it’s easy to wonder why it matters that streaming is intra-school, rather than inter-school. Or, in other words, why we shouldn’t have more grammar schools.

To make matters worse, critics of grammar schools don’t seem to see that the case for creating more grammars within the current educational ecosystem may actually be a lot stronger than the case for never banning them in the first place. Althouhg such critics as Vince Cable repeat an historic analysis of a two tier system of the ‘best and the rest’, and a deterministic test at age 11, the creation of new grammar schools in the current climate could easily avoid this outdated critique.

Unlike in my parents’ generation, we now have free schools, faith schools, academies, UTCs, comprehensives, studio schools, and City technology colleges. Streaming will be used in many of these. There’s no need to impose grammars where they’re not needed, or where they would not enhance the local offering. But in my own constituency of Salisbury, the nationally outstanding grammar schools add a huge amount to an impressive educational ecosystem made up of a range of school types for 11-16 year olds.

One particular benefit that isn’t often acknowledged, but is clear from Salisbury’s experience, is the scope for grammar schools to have large sixth forms. The grammars’ sixth forms can take in a high number of additional pupils from other local schools, which also enables them to offer a wide range of subjects at A-Level. Those who don’t want a child’s whole schooling to be determined at age 11 should actually be in favour of grammar school expansion: it offers additional opportunities for later developers at sixth form.

The old system could be improved, of course – with multiple entry points, not just at 11 and 16 but with an additional stream of entry at 13+. However, the quality and diversity of non-selective schools, thanks to the Free Schools programme and academy reforms, means that grammars don’t need to be seen as the only ‘gold standard’ in our education system. A grammar school may simply not offer the right learning environment for a pupil even if they would be selected on academic ability alone. The culture around learning and the needs of individuals are not always best viewed through academic potential: unless social skills and wider developmental needs are met then academic credentials are of limited use.

These challenges met, the simple policy point remains. ‘Adding value’ to ensure every child’s potential is maximised from whatever their starting point is must guide our approach to further reform. The willingness of non-selective schools to adopt streaming shows that academic selection works. And since it does, we should not be afraid of creating more grammar schools to extend the options that young people can benefit from.