It’s a “survival imperative” that independent schools must work with their state sector neighbours - or they will become “more and more marginalised and the sector will diminish.”

That’s the warning from Mike Buchanan, the executive director of the Headmasters’ and Headmistresses’ Conference (HMC), a body which represents 350 independent schools, including Eton and Harrow.

Back in 2016, the government threatened to cut the charitable status of independent schools that didn’t do enough to support state schools.

In its green paper, entitled Schools that Work for Everyone, it said larger independent schools should sponsor local state schools and be responsible for bringing them to ‘good’ or ‘outstanding’ Ofsted ratings within a set time frame

At the time, Mr Buchanan, then headmaster of Ashford School, an independent school in Kent, is reported to have likened the situation to a ‘forced marriage’  and said the UK’s independent schools already shared much of Prime Minister Teresa May’s vision and that she was “knocking at an open door.”

Speaking at the Independent Schools Conference in central London yesterday, he said: “The challenge for us as independent schools is to share what we have - to get out there and help.

He added: “It’s not a nice thing - it’s a survival imperative that we must engage with other communities, and I know lots of schools do - my school did and still does. But if it doesn’t move up the priority list then actually we are not going to survive because we will become more and more marginalised.

“Some schools will survive - yes of course they will  - but the general sector will diminish.”

In May this year The Department for Education stepped away from its threat to remove independent schools’ tax breaks if they fail to support state schools.