All three main political parties have now acknowledged, one way or another, that current inspection arrangements do not provide a fair and reliable judgement on school performance and reform is needed.

Yet, while there is an agreement of the need for change to school inspection, the solutions proposed could not be more different.

The choice being presented to voters appears to be rather binary: do you want to get rid of Ofsted or have more of it?

Watch: Ofsted boss says no-notice inspections being considered

Labour: Plan to abolish Ofsted

Conservatives: Funding pledge in manifesto

There will be very few people in education lining up to commend the proposals announced by the Conservatives last night to double down on school inspection.

Indeed, having spent the last two years taking a research-led approach to the development of a new inspection framework, I suspect there are many in Ofsted, too, who are inwardly seething that political whim could now dictate the how, what and when of school inspection.

Last year, I chaired the independent Commission on School Accountability. Through this work, we found that inspection had played its part in helping to lift educational standards in England to good, but was incapable of driving the system on from good to great.

Inspection is a powerful tool for driving compliance to set criteria or minimum standards, but an absolutely lousy one for unleashing greatness in a system. At best, inspection is a distraction on the journey from good to great, at worst, it works against improvement by incentivising the wrong actions and behaviours.

The vast majority of schools in England are now “good” or better - around 85 per cent overall. Yet the way in which we hold these schools to account is having a deeply negative impact, which limits the ability of the system overall to improve.

High-stakes inspection acts as a brake on improvement in schools, by encouraging short-termism, limiting ambition and stifling innovation. More inspection will not release this brake.

The simple truth, often repeated, is that schools are only as good as the professionals that work in them. Yet evidence shows conclusively that we lose too many good people from the profession prematurely as a result of high-stakes accountability, either directly, as a result of falling foul of a dodgy inspection judgement, or indirectly, as a consequence of the workload, stress and anxiety caused by it.

We are in the middle of a recruitment and retention crisis and no-notice inspection, in particular, is likely to make this bad situation even worse.

The idea that an inspector can walk into your school at any point without prior warning will cause intolerable stress for school leaders and teachers. It will result in more wasted time for inspectors while arrangements are frantically put in place to meet their needs and could further incentivise competition over collaboration as system leaders could well be less willing to risk being off-site when in the inspection window.

In return, it will provide zero additional insight. Ofsted already has the powers to conduct unannounced inspections where it is deemed to be necessary. It makes absolutely no sense to apply no-notice in situations where there is no good reason to do so.

Likewise, the obsession with poor behaviour in schools is immensely frustrating. There is no evidence to suggest that behaviour, particularly at primary school, is anything like the problem that these statements make it out to be. And surely, in the minority of schools where behaviour problems do exist, would we not be better off providing more help and support, instead of an additional day of inspection?

The accountability commission concluded that to improve further, the government need to rebalance holding schools to account with helping them to improve. We said Ofsted needs to focus their efforts on the small fraction of schools that are struggling to provide a good standard of education and provide stronger diagnostic insight on what is going wrong to help them improve more rapidly. We’ve argued that these inspections should be as long as it takes for them to be helpful. Arguably, additional investment in an inspectorate to do this well could be money well spent.

School leaders welcome accountability. Children only get one chance at an education; it is right that processes are in place to monitor the quality of education provided in every school and prompt action to improve where needed. Quite frankly, the stakes are too high not to.

But as far as inspection is concerned, eye-catching policies that are designed to attract the attention of voters are unlikely to deliver tangible benefits for pupils, parents or schools.  England’s schools are already among the most highly regulated in the world. More high-stakes inspection could, perversely, make it more likely that we’ll be left behind internationally over the coming years.

Nick Brook is deputy general secretary of the NAHT headteachers’ union and chair of the NAHT’s accountability commission