Long before we had "free schools" we had the real free schools. And they offered true freedom to their pupils, not a variation on the battery- hen approach to education that keeps young people pointed towards the examined curriculum.
Today, only one of those genuine free schools remains in the UK. Summerhill will reach its centenary within a decade, yet it still has the power to shock.
Nowadays the phrase "child-centred education" tends to be said with sneers, league tables have primacy, and if a pupil elects to skip lessons their parents face jail. The free range that Summerhill gives its pupils arguably looks even more radical to teachers now than it did back in 1921 when A.S. Neill founded it.
Over the years, the school has been dismissed as a one-off oddity, a failed experiment and an eccentric irrelevance. Yet Summerhill was decades ahead on a range of approaches that mainstream teachers only began taking more seriously later, including student councils, restorative justice and pupil-led learning.
In one of Neill's letters to TES in 1947, he described how he enjoyed doing maths puzzles on train journeys but wanted advice from other teachers to answer a child's conundrum.
"My pupils' minds enquire more than I explain," he wrote. His delight at students asking questions he could not answer would have helped him to fit in well with today's proponents of enquiry-based learning.
The current tide of education in England may seem to be rolling against such progressive approaches. But that is precisely the reason why it is worth looking at Summerhill once more: the school has zigged where others have zagged, sometimes, surprisingly, by offering more traditional styles of teaching.
Her Majesty's Inspectors got it right in their report on the school in 1949: "What cannot be doubted is that a piece of fascinating and valuable educational research is going on here which it would do all educationists good to see."