Headteachers from 31 counties across England have sent the government an invoice for £3.5 billion – the amount they believe they would receive under a fairer funding system.
Accompanying the invoice is a letter to chancellor Phillip Hammond warning that the schools have "reached a point of no return" because of the pressures being placed on their budgets.
The letter, from the Worth Less? campaign group representing 5,500 schools, say these pressures have forced them to rely on parents for financial contributions and prop up budgets with pupil premium money aimed at disadvantaged children.
School funding difference
The £3.5 billion represents the difference between the amount of money pupils attract on average across the campaign's schools, compared with those in Westminster.
The national funding formula being introduced this year will simply "lock in previous historical funding injustices", the letter states.
It says: "Our schools need to be given the same 'tools' to deliver as other better-funded parts of the country. Our children all sit the same examinations and our schools are judged by the same Ofsted criteria.
The letter comes the day after education secretary Damian Hinds told MPs: "There is more money going into our schools in this country than ever before in the history of the country."
But, while real-terms spending on schools has risen over the past two decades, it fell by 4 per cent between 2015 and 2017 – and is being frozen for two years until 2019.
The Department for Education's permanent secretary Jonathan Slater yesterday admitted that the number of maintained schools going into deficit has increased during the past year, with academies set to see a similar trend.
In response to the letter, a DfE spokesperson said: “The campaign’s calculations are thoroughly misleading and ignore the fact that under our national funding formula, funding is based on the needs and characteristics of each individual school.
“We are investing an additional £1.3 billion in school funding over and above existing plans, with core schools funding rising from almost £41 billion in 2017-18 to £43.5 billion in 2019-20.
“There are no cuts in funding. Every school will see an increase in funding through the formula from this year. In 2019-20, all secondary schools will attract at least £4,800 per pupil and all primary schools will attract at least £3,500 per pupil.”