Four in five state schools will be worse off financially next year than they were less than five years ago, unions have claimed.

A new analysis by the School Cuts coalition calculates that most schools in England (more than 80%) will have less funding per pupil in real terms in 2020 compared to 2015.

Ministers announced plans last month to invest an extra £7.1 billion in schools in England over the next three years (up to 2022/23).

This includes increasing the core schools budget by £2.6 billion in 2020/21.

But the coalition’s analysis says that there will still be a shortfall of £2.5 billion next year.

It goes on to say: “School costs are estimated at 2.9% for next year which is significantly higher than the minimum funding increase of 1.84%, so roughly a third of schools will have to make further cuts next year.

“At the moment, 91% of schools have real terms cuts compared with 2015. This will go down to about 80% in April.”

Geoff Barton, general secretary of the Association of School and College Leaders (ASCL), said: “After years of denying that there is a school funding crisis the Government has finally done the right thing by investing desperately needed extra money into our beleaguered education system.

“But analysis by the School Cuts coalition shows the additional funding is not enough to repair the damage that has been done to our schools and colleges and that further investment is required. We are not being churlish, we are just stating the facts.

“The funding crisis is not over.”

Kevin Courtney, joint general secretary of the National Education Union (NEU), said: “Prime Minister Johnson has made lots of empty promises on school funding – but his numbers don’t add up.

“The latest funding announcement falls well short of settling the shortfall for every child. And crucially it fails to reverse the cuts schools have suffered since 2015.

“It’s unthinkable that our schools have to go on like this – losing support staff, shedding subjects and cutting back on basic maintenance just to balance the books.”

Luke Sibieta, research fellow at the Institute for Fiscal Studies, which has examined education funding, told the PA news agency: “Total school spending per pupil has fallen by 8% after inflation since 2009 and by 5% since 2015.

“The Government has committed to extra funding of £4.3bn per year in today’s prices, which will be enough to reverse cuts on average.

“However, that won’t fully come in until 2022. It’s therefore unsurprising to see analysis showing that most schools will have lower budgets in real-terms next year as compared with 2015.”

The Government has said promised extra cash for schools over the next three years fulfils Prime Minister Boris Johnson’s commitment to boost spending and schools that have been underfunded will get the biggest increases.

The move came after years of lobbying by heads and teachers for more cash.

A Department for Education spokesman said the Government’s school funding announcement means all secondary schools will receive at least £5,000 per pupil next year while all primary schools will get at least £4,000 from 2021-22, adding that the biggest increases will go “to the schools that need it most”.

– The School Cuts coalition is made up of six unions – ASCL, NEU, The National Association of Head Teachers (NAHT), GMB, Unison and Unite.