Will Tanner is Director of Onward and a former Deputy Head of Policy in Number 10 Downing Street.

“The Tories’ Academy system is simply not fit for purpose”, raged Angela Rayner, Labour’s Shadow Education Secretary, at last year’s Labour Party Conference.

A future Labour Government, she announced, would “instead focus on delivering what works to get the best results for pupils” by abolishing free schools and bringing academies under greater local authority control.

The uncomfortable truth for the Labour Party is that “what works best for pupils” seems increasingly to be studying at a school free from local control, just like an academy or free school.

According to official performance data published last week, the schools which deliver the most progress for pupils are free schools. If you track how pupils progress from the end of primary school to the end of secondary school, free schools achieve nearly a quarter of a grade higher in each qualification than other similar pupils nationally. This is double the average progress score achieved at the next best type of school, converter academies.

This is not, it seems, a fluke or fake news. It is the second year in a row that free schools have outperformed all other kinds of school on the government’s Progress 8 measure. The gap between free schools and other categories of school has also grown year-on-year. The best multi-academy chain in the country – Star Academies – achieved an average of nearly one and a half grades’ worth of progress for its 378 pupils last year.

In contrast, the type of school that Rayner would like all schools to be – local authority maintained schools – delivered an average Progress 8 score of -0.03, meaning pupils, if anything, marginally regressed over their years in secondary school compared to other similar pupils in England.

This is just the latest in a long line of evidence that giving schools more autonomy over what and how they teach delivers improved results for children. It is telling that 31 per cent of free schools are rated ‘Outstanding’ by Ofsted, compared to 21 per cent of all schools. It is true that sponsored academies have lower Progress 8 scores than other kinds of school, but according to research by the Department for Education published last week: “pupil outcomes in sponsored academies have typically improved since their formation in comparison with sets of similar schools”.

Perhaps unsurprisingly, parents have noticed. According to research from the New Schools Network, primary free schools have been the most popular school type for the last five years running, and at secondary level have proved the most popular kind of school for the last four years. So, as if planning to abolish the most successful type of school wasn’t enough, Labour also wants to close down the schools that are most popular with parents.

But nowhere is the short-sightedness of Rayner’s schools policy more visible than in East Ham, where Brampton Manor Academy is transforming the fortunes of a community long beset by disadvantage. When Labour left office in 2010, Brampton Manor School was a good and improving secondary in a tough neighbourhood. A year later the school converted to academy status and in 2012 it opened a sixth form to direct its uncompromising approach to excellence to school leavers.

In 2014 the sixth-form generated its first offer from an Oxbridge college. The following year the number had risen to five. Last year, 20 children were given places at Oxford and Cambridge. This year the school doubled that, with 41 pupils being offered a place at Oxbridge, two thirds of which will be the first in their families to go to university. It’s nickname, the “Eton of East London”, is well-earned: Brampton Manor delivers more working class children from East London to Oxbridge than from some of the most exclusive and expensive private schools in the country.

When asked to reveal the secret of Brampton Manor’s success, its principal, Dr Dayo Olukoshi, talks explicitly about the benefits of the academy model. He talks proudly of his work to “eliminate unnecessary bureaucracy” and to “empower our staff to take risks and innovate in their classrooms”. The school has a study centre open from 6am to 7pm, funded by the Pupil Premium, and offers students Oxbridge preparation classes to drive higher levels of university success.

All of this would be more difficult, if not impossible, if Brampton Manor was bound by the kind of local authority strictures that the Labour Party have pledged to reintroduce.

The most galling aspect of Rayner’s schools policy, however, is the airbrushing of the Labour Party’s foundational role in the academy movement from 2002, and the wilful rejection of cross-party endeavour to expand those freedoms to every school. Academies were first championed by a young Andrew Adonis in the Downing Street Policy Unit, and later the House of Lords, before being embraced wholesale by David Laws and Nick Gibb under the Conservative-Liberal Democrat coalition.

But gone are the days when the Labour Party recognises the role of academies like Brampton Manor in “bringing new hope and breathing new life” into local communities, as Tony Blair heralded in a speech in 2005. Today the policy is nothing more than a “Tory academies system”.

Labour says it wants to deliver “what works to get the best results for children”, yet it is increasingly evident that the winning formula is the exact opposite of its one-size-fits-all pledge to reinstate bureaucratic control. If the innovation-embracing approach of schools like Star Academies and Brampton Manor delivers whole grades’ worth of pupil progress and places at Oxbridge, that is the model we should be pursuing, not restricting.

Thankfully, the revolution started under Blair, and radically accelerated under Michael Gove, has already liberated thousands of schools and millions of pupils, and now more than half of all children in England benefit from the freedoms of academies and free schools. That is an auspicious milestone, but it is clear the battle is not yet won.