The education secretary Nicky Morgan has today launched a bill designed to sweep away any obstacles when as many as 1,000 “struggling” schools convert to academies. It is designed to prevent appeals and reviews, and will impose a new duty on councils and governing bodies, whatever they believe is best for their children, to actively support the change to academy status. Morgan justifies this on the basis that “a day spent in special measures is a day too long where a child’s education is concerned” and that it will allow education experts to help out poorly performing schools as soon as possible.

The underlying claim here is that academy conversion is a simple process that leads not just to improvement, but to that school becoming outstanding. Morgan may believe this, but it is hard to find any evidence to support it. The education select committee, chaired by Graham Stuart of the Conservatives, carried out a thorough review of academies and free schools and found no such evidence. “Academisation is not always successful nor is it the only proven alternative for a struggling school,” was one of their conclusions. Indeed, Morgan has ignored their recommendation that “the government should stop exaggerating the success of academies”.

Similarly, the National Foundation for Educational Research found that “no significant improvement is seen in the rate of improvement of GCSE results for academy schools over and above the rate of improvement in all schools”. The Department for Education itself, in a high court case last summer, argued only for “marginally higher” achievement for academies rather than the dramatic results that Morgan is claiming.

Our own analysis at the Local Schools Network has consistently shown that when schools are converted to academies their improvement is no better than similar local authority schools. Indeed, in last year’s GCSE figures, the results of sponsored academies consistently fell more than the results of non-academies.

In two of the largest academy chains Ofsted rated at least half of the schools 'requires improvement' or 'inadequate'

After Ofsted inspections carried out since conversion, 8% of primary sponsored academies, and 14% of secondaries, are currently rated “inadequate”. It is not clear what the government’s solution is for children in these schools in special measures. The evidence would suggest the best solution might be to hand them back to local authorities, but this is unlikely to happen under this government.

When Morgan talks of bringing in “education experts”, she is referring to the academy chains that now dominate the government’s approach to education. Far from knowing exactly how to make a school outstanding, most underperform compared to local authorities. The Department for Education’s own analysis found that, of the top 20 chains, only three had performances, in terms of value added, that were above the national average.

Ofsted is not allowed to directly inspect chains, as it does with local authorities, but has carried out mass inspections of the schools in specific chains. This has resulted in highly critical conclusions on several chains. In two of the largest chains, at least half of the schools were rated “requires improvement” or “inadequate”.

There have been successful campaigns against the conversions of schools. At Hove Park school in Brighton academisation was fought off after parents voted against it in a council-run poll. At Snaresbrook primary school in Redbridge, the DfE agreed not to go ahead with academy conversion after parents won the support of the Conservative-run local council. It now appears that such actions would be prevented under the new legislation.

The government’s claims about the effect of academy conversion are assertions based on ideology, not data. In this light it is especially worrying that councils and governors are to be forced to ignore both the evidence and their conscience. Instead of a duty to do what is best for the children, their duty now will apparently be to support government policy.