Mark Lehain is Director of Parents and Teachers for Excellence, and founder of the Bedford Free School.

Robert Halfon is a brilliant exponent of an expansive, effective, and inspiring conservatism. Few have done more than him to challenge Tory stereotypes and champion policies that cut through to the wider public.

However, I worry that when he addresses educational matters, as in his column on Wednesday, he undermines all the other great things that he has done over the years. It contained quite a few errors and misconceptions, but I’ll just focus here on the four biggest.

Exclusions rates – they’re up, but for good reasons

Halfon correctly states that exclusion rates are up in recent years, but omits two important facts. First, that the rate is no higher now than they were a decade ago; secondly that the increase is largely down to a deliberate decision by Michael Gove to help headteachers make their schools safer, after numbers were kept artificially low under Labour.

In the bad old days, heads operated in a regime where if they expelled a student a group of strangers on an Appeal Panel, with little understanding of the challenges schools face, could overturn things.

This had two terrible consequences: bad behaviour went unchallenged, as heads avoided expulsions in case they were overturned and their credibility undermined; and schools were literally forced to take back students who had assaulted staff and students, or brought weapons into school. For many heads it just wasn’t worth the risk to their school’s reputation, and behaviour and learning suffered.

Conservatives should be proud that Gove put a stop to this and backed headteachers, whilst ensuring fairness through introducing “Independent Review Panels” instead. Schools today are safer, happier places because of this change.

Exclusions do not lead to crime and prison

Another error is the way Halfon links exclusions to crime, saying “we know that pupils who are excluded from schools are twice as likely to carry a knife, and 63 per cent of prisoners report having been excluded from schools in their youth.”

It’s not exclusions that make people carry knives or go to prison, but other underlying issues in families and communities that cause them all. Schools are places of learning, and we should not ask them to compromise their purpose or safety to address such complex underlying problems.

Different rates of exclusion for different students do not mean discrimination is occurring

The law is clear that exclusions should always be a last resort. School leaders take this seriously, and bend over backwards to support students and avoid exclusion if they possibly can.

Sadly, in recent years a small but influential group of activists have been successful in convincing some politicians and journalists that, because some groups of students experience higher rates of exclusion than others (e.g. those on Special Educational Needs registers), there is systematic discrimination in our school system.

When Halfon writes that “children with special educational needs account for around half of all permanent and temporary exclusions”, he does so to reinforce this view above.

However, the statistic in isolation is misleading – and he knows this, as it’s been pointed out to him repeatedly. As the teacher Andrew Old wrote in a series of blogs challenging the activists’ claims: “Children are not excluded for having SEN. They are excluded for one of the main reasons they end up being given the SEN label, their behaviour.”

High student mobility does not mean pupils are being dumped

Finally, I worry at how Halfon referenced data published by Ofsted regarding schools with high levels of student mobility during GCSE years.

Ofsted has not “identified” these schools as ones who are dumping kids: they’ve just said that they wanted to examine why these particular schools were experiencing high pupil turnover, which is perfectly reasonable.

He also wrote that “over 19,000 students disappeared from the books”, making it sound like schools made them vanish. This is just incorrect. Schools are not allowed to remove a child from their roll without permission and evidence of where they are going on to be educated.

As Ofsted said when it released its statistics here, half of those that moved went to other state schools, another chunk into home education, and some more probably to independent ones. Knowing what’s happened with the remainder is important, but it’s not right to judge institutions without having all the facts.

Education is a big success for the Conservatives

While we’ve definitely not got everything right, I would argue that it is disadvantaged children who have benefited most from Conservative school reforms. Smearing schools, and confusing correlation with causation, doesn’t help anyone. Restricting how schools can keep their staff and students safe would damage vulnerable pupils most.

There is so much that we can be proud of having achieved in England’s schools since 2010. The list of successes is quite incredible: a stronger National Curriculum, more rigorous exams, fairer funding, more autonomy for schools and staff, hundreds of popular free schools, a more enlightened Ofsted, proper phonics teaching… I could go on and on.

But we mustn’t forget though that all of these achievements rely on safe, orderly schools. Let’s be careful as fix the bits of the system that aren’t working, and not inadvertently throw away all our hard-earned gains by letting behaviour slide like it did under Labour.