In the end, it was the sports kit that persuaded us to pull the plug: two technical training tops at a cost of £90. A directive had come down from the senior school that all pupils must be in new gear from Kukri (official supplier to county cricket clubs and Commonwealth Games England) by the start of the Michaelmas term. I replaced what our sons had outgrown in the school’s uniform shop (five items: £200), but baulked at spending another £100 when their old training tops still fitted.

School fees are already unaffordable – and that’s before you factor in VAT at 20 per cent

Our sons had been in prep school since we bolted from London after the lockdowns to a part of the country we barely knew. The prep school was an attempt to assuage our anxiety about what they’d missed during home-schooling in a household with a new baby sister and parents who worked throughout.

But then the school put the fees up twice – citing concessions made during Covid – and our mortgage rose by £500 a month. The headteacher was aware of this: there was a queue of parents each term trooping in to see her about the cost of living. The likely general election loomed ahead of us, and Labour’s pledge to put VAT on private school fees.

We had other concerns. Saturday school was optional (involving ‘academic enrichment’ but nothing from the curriculum), but we had to pay an extra £4,000 a year for it. The boys were only there 60 per cent of the time. And having thought we’d parked our concerns about their education, I realised during the nine weeks of their summer holiday that my eight-year-old couldn’t tell the time and both he and his nine-year-old brother used capital letters randomly. These were things I’d tried to fix during lockdown. What the hell had the school been doing?

We found out about a village primary where friends’ children were flourishing in small classes, and what it lacked in pricey uniform and Astroturf pitches, it made up for with forest school and simple initiatives like Year Six children visiting the reception class to read and play with the younger ones.

We were lucky: I got places there. The cost of those training tops helped make our final decision. Our sons started at their new primary in January and we haven’t looked back.

As it turns out, we may have made the switch just in time. Their new school is almost at capacity and we keep hearing about other families giving notice at their prep schools. ‘Our mortgage has gone up £900 a month,’ one mother tells me. ‘We were borrowing money just to live on.’ For middle-class professionals (which I define as working parents without inherited wealth, paying school fees out of their net income), private school fees are already unaffordable – and that’s before you factor in VAT at 20 per cent.

Two months ago, a group of parents describing themselves as ‘non-wealthy’ launched a campaign against the VAT raid which, they argue, will hit hard-working families disproportionately. The face of the campaign is an NHS data analyst, Tony Perry, who has two children: one, with additional needs, who attends a private day school in Ascot. But even extremely well paid professionals are struggling. ‘I’m on £200,000, plus bonus,’ says one father of three. ‘But if we get an unexpected expense, then we can’t pay.’

Of course we are well-off by most people’s standards; ludicrously, embarrassingly so. But over the past few years household finances have deteriorated significantly, even for the hitherto affluent middle classes. For parents like us paying for schooling out of PAYE salaries and a freelance income –and who’ve already had to shoulder the costs of inflation-driven fee rises – another hike of 20 per cent is impossible.

A much larger exodus of children from private to state schools is on the way. ‘We think it could be quite a lot of parents,’ says Barnaby Lenon, chairman of the Independent Schools Council (ISC). ‘What is most likely to happen is there will be individual private schools that suddenly decide they have to close due to a shortfall in demand.’

The ISC commissioned its own report on VAT and pupil movement in 2018, before Covid, Brexit and Ukraine squeezed household finances to the max. The report, by Baines Cutler, estimated that more than 120,000 students would move into state schools. As a result, the policy would, by its fifth year, cost £400 million per annum.

Labour likes to claim its plan will net around £1.6 billion. It prefers to quote last year’s report by the Institute for Fiscal Studies (which came up with the much-quoted £1.6 billion figure) and assume that VAT would lead to only a 3-7 per cent reduction in private school attendance. That’s 20,000-40,000 children out of the 570,000 who currently attend private schools in England. Many think this estimate is ludicrously low.

‘I’m aware that the IFS basically argued that “fees have risen a lot over the past decade and state school funding has not, so this suggests that independent school parents can wear it”,’ says Helen Pike, master of Magdalen College School in Oxford. ‘But did fees rise 15-20 per cent in one year, and as a tax on the consumer?’

Crucially, the IFS report failed to consider ‘demand elasticity’. ‘Many people paying school fees are already pushed towards the margin – that is what they [the IFS] completely missed on this report,’ says one economist. Teaching unions are watching anxiously. If Labour has overestimated how much revenue the policy will raise, then it means it has also wildly underestimated how much spending will be needed on state schools to provide for the new intake.

Meanwhile, our young sons, oblivious to all this, are flying at their village primary. They do PE in Aertex shirts and shorts that cost a tenner. They’re benefiting from a shorter day and a less-helicoptered environment: my eight-year-old’s tics and fidgeting, symptoms of his ADHD, have all but disappeared. So too have my nagging worries that, in the long run, being privately educated may not do them any favours when they apply for university and internships. I’m even looking at some ‘academic enrichment’ in the form of our first proper holiday for six years. If you’re thinking about making the switch, better beat the rush – and do it now.