Occasionally - shocking though it may seem - departments are required to propose policies that they don’t want. When there’s a last-minute request from No 10 for a speech, or the Treasury after a spending cut, a response that is often deployed is called “bring out your dead”.

Departments offer up something so unappealing that it is rejected out of hand. And, hopefully, the issue then goes away. Every department has a metaphorical bucket where these “dead” proposals are stored: the hackneyed, the unachievable, and the downright silly.

Deep (deep) down in the Department for Education’s bucket is doing something about charitable status and the independent sector.

And lo! In the Green Paper, it was resurrected - fresh from its last appearance in, um, Labour’s 2015 manifesto.

This specific version says that independent schools must sponsor academies, or provide more bursaries, in return for their charitable status and associated tax advantages.

What’s fascinating is the way in which the issue has been elevated to totemic status. It is the battle standard beneath which each side gathers.

On the one side are those who rage at the state funding some of the richest and most privileged institutions in Britain. On the other, the disparate independent sector and its supporters come together to circle the wagons against state intrusion and interference.

‘It’s just a mirage’

And here’s the thing, this totem, this issue, this banner under which both sides ride to combat: it’s a fake. A mirage. A chimera.

The tax breaks are worth an estimated £250 million a year. When split across about 1,000 charitable private schools, it’s a couple of hundred pounds per pupil. Not nothing - but close to it. And independent schools do genuinely engage in a series of partnerships worth more than this - Independent Schools Council data suggests 87 per cent have formal collaborations with the state sector, covering about 10,000 state schools and up to 160,000 pupils.

But even if this latest sally comes to nothing (and past history, plus some pretty explicit guidance from the Charity Commission that says it’s up to independent schools to define their own public benefit, says it will), the broader point remains, which is that its existence is an issue that benefits neither side. For, if it went away, there would be nothing to attack the private sector with. And that money would not lead to a transformation of the state sector either.

So wouldn’t the smart thing be for independent schools to give it up? To call successive governments’ bluff. To declare that independent schools provide a range of benefits, but that the tax break itself is tangential to that and a distraction from bigger issues. Renounce charity status, if needed. Or just don’t claim the relief. Campaign to government for a change in the law.

Then we can have a debate on the real issues: school improvement in the state sector, and the financial sustainability of the independent sector outside the South East. And we can stop having the tax break tail wag the state-independent partnerships dog.

Jonathan Simons is a former head of education in the Prime Minister’s Strategy Unit under Gordon Brown and David Cameron