As the Government has decided, after several happy years, to revive the annual furore over grade inflation, this year has also seen a return of the traditional hang-wringing about the role and performance of private schools.

On the one hand Lord Lucas, a Conservative peer and editor of the Good Schools Guide, suggested that universities will prioritise state-educated pupils. On the other, falling back on teacher assessment has seen the gap between private and state school outcomes grow wider than ever.

Worse, as I pointed out this morning, in the long run grade inflation can only benefit better-off pupils as universities are forced to use different metrics to sift applicants – especially if it sees a renaissance of interviews and even more weight placed on extra-curricular activities.

Unfortunately, as Rob Colvile of the Centre for Policy Studies observed this morning, the ritual debate about private schools too often focuses on how they could be brought into line with state school performance, rather than being a spur to try and improve private schools.

In this framing, any difference in outcome from private schools arises entirely from irreplicable conditions, presumably their budgets and the social background of their pupils. This has the handy result of avoiding any difficult questions about the things private schools do which state schools could do to. In the past this would primarily be holding on to classical methods of teaching and school organisation whilst the state sector experimented with various, often disastrous, alternatives.

But in the aftermath of the pandemic, it would also pose pointed questions about things such as the level and rigour of remote teaching offered to pupils, as well as the basic question of how keen an individual school was to stay open at all, and the level of remote learning they provided whilst pupils were off-campus.

Of course, a sudden shift to remote learning would have put better-off pupils at an advantage, as they are much more likely to have had the necessary infrastructure in terms of broadband, devices and so on. The Learning in Lockdown report from the Sutton Trust found that private schools were more confident in their pupils’ online access, switched to online more quickly, and reported higher attendance. Focus groups also found private schools parents being happier.

But we shouldn’t pretend that money is likely to be the only difference. Whilst the Sutton Trust don’t seem to have monitored differences between traditional comprehensives and academies and free schools, we have also already seen clear evidence of different sorts of state school taking very different approaches to, for example, reopening. As I noted previously:

“It is surely no coincidence that it’s the major academy chains – Reach 2, Harris, Oasis and GEP – which are backing the Government’s plans to restart schools, alongside the headteachers’ unions. The founder of Oasis, Steve Chalke, has gone so far as to attack opposition as ‘middle class’, highlighting the disproportionate impact extended closure will have on children from less advantaged backgrounds.”

What this illustrates is that material circumstances are not destiny. Even if you start with less, it is still possible to do better or worse with what’s available to you. (It also perhaps suggests that parental agency, as well as money, helps drive positive change in school attitudes – the very logic of the school choice agenda).

That’s why one virtue of private schools is that they provide an independent barometer against which the impact of various reforms to state education can be measured. The point isn’t whether or not a state school can do what a private counterpart does. But if one set of reforms sees the private/state gap grow wider, and another set narrows it, we can fairly conclude that the latter reforms are delivering better outcomes.

Michael Gove touched on this point when he suggested that the best way to get rid of private schools would be to make state schools so good that it didn’t make sense to spend the money.

Until then, we should sternly resist those who suggest closing the attainment gap by cracking down on private schools. Doing so would only bring even more wealthy parents back into the state sector, which instead of lifting all boats would just see house prices in the catchment areas of good schools climb even higher whilst their kids took a share of the state education budget to boot.