Leaked Department for Education plans for schools to receive a £2.8 billion funding boost are no more than a “Santa wishlist”, insiders have cautioned.

A document that emerged last night led many to believe that the department had been successful in negotiating a substantial injection of new funds from schools from 2020/21.

But Tes has been told that the figure - and the policies that depend on it, such as extra teacher pay - represent little more than the DfE’s opening bid in negotiations with the Treasury.

The actual figure, due to be announced by chancellor Sajid Javid next Wednesday, will be “nowhere near” the sum quoted, insiders warn. 

Teaching unions say even that best-case £2.8 billion cash boost for primaries and secondaries is a fraction of what schools need to redress years of funding cuts.

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The figure was revealed in a leaked DfE document seen by the Guardian and is said to include £800 million for children with special educational needs and disabilities (SEND), with a possible £800 million extra for sixth forms and further education colleges.

But it is less than a quarter of the £12.6 billion that unions have called for over the next four years to reverse “devastating” funding cuts.  

Mary Bousted, joint-general secretary of the NEU teaching union, said the leaked document was £8 billion short of what is needed.

“Obviously any extra money for schools will be welcome because schools are desperate for funding,” she said.

“The problem is this just isn’t enough. It will not make enough of a difference to counteract the scale of funding cuts that schools have already experienced.”

Headteacher Jules White, coordinator of the WorthLess? schools funding campaign, which is organising a march of around 5,000 headteachers on Downing Street on 27 September, said more detail was needed on how the cash would be spent, including whether it would be paid in a single year or spread over future years, and whether it would be swallowed up in costs such as increased employers’ contributions in teachers’ pensions.

“I’m not going to say this is hopeless because schools funding is exactly what we’ve been campaigning for,” he said. “The only way you can make a really thorough assessment is to see what the breakdown is.

“If the government makes serious unbreakable pledges, then we will celebrate from the rooftops but we won’t be blindsided by electioneering.”

Luke Sibieta, an education specialist at the respected Institute for Fiscal Studies also reserved judgment and raised the pensions issue.

“I think the question is whether this £2.8 billion is being provided in a single year or over a longer period of time,” he said.

“It is also unclear whether the funding increase will include supporting schools to meet the increased employer contributions to teachers pensions.

“It is spending £848 million doing this for 2019-20 but hasn’t made commitments beyond that. It would cost £1.5 billion a year to meet the increased costs for schools so the question is does the £2.8 billion include £1.5 billion increased pension costs?”

Geoff Barton, general secretary of the Association of School and College Leaders, called for more detail and for extra money to be allocated immediately.

He said: “Schools and colleges will welcome any genuine improvement to funding after a period of austerity which has been extremely challenging and has caused a great deal of damage. But they will need some convincing that any funding commitment really does address the crisis and isn’t simply part of a strategy for a forthcoming general election.

“It needs to be part of a longer-term commitment to reverse the education cuts because the sums of money being discussed are not enough to achieve that objective on their own.

“We are pleased to see that there is a proposal to improve teachers’ pay but once again we need to see the detail and be sure that this would be fully funded by the government and not an additional unfunded cost on schools.”