Headteachers have warned that school leaders are faced with making more cuts because they are still seeing funding drop in real terms.
Geoff Barton, general secretary of the Association of School and College Leaders, said that heads and governors were still faced with uncertainty over how to set their budgets from next September – despite funding pledges from the government.
And he said this could result in larger class sizes and more teaching assistants posts going.
Quick read: DfE announces '£14bn' increase
The Department for Education announced a major funding increase for schools last month but unions in the School Cuts Coalition have warned that this will still leave 80 per cent of schools worse off than they were four years ago.
Mr Barton said that heads welcomed investment in education but that unions are concerned that it will not be enough to stop further cuts.
He also criticised the DfE for announcing the extra funding total as £14 billion, which he said was twice the amount schools will actually receive.
Speaking at a Stop the Cuts Coalition meeting, he said: “Between us, we represent the nation's school leaders. They will at the moment, with their governors, be making decisions about next September’s curriculum. None of those decisions are going to be helped by the way the presentation of this material has been put out there.
“So, for example, we know the original claim of £14 billion wasn’t £14 billion, it was £7 billion.
“We know the promise of £30,000 teaching salary at the start of a teacher's career is going to come out of this money, so what does that mean?
“What leaders will be doing now is saying: ‘Can I make different decisions about my curriculum?' Knowing that if you are going to have to continue to make savings, the only way you can do that is by large class sizes, shrinking curriculum, losing teaching assistants and losing other staff.
“At the moment, we are not in a position to know what those decisions should look like and certainly the evidence today is giving a fairly bleak picture of schools having to continue to make reductions.”
Earlier this year, ministers announced plans to invest an extra £7.1 billion in schools in England over three years from next year.
The Schools Cuts Coalition says that the government has promised to give schools £1.9 billion more next year. However, the unions say this falls short of what is needed.
Responding to the School Cuts Coalition figures the Department for Education said: “This government has announced the biggest funding boost for schools in a decade, which will give every school more money for every child. We are investing a total of £14 billion more in schools over the next three years to 2022-23.
“This means all secondary schools will receive a minimum of at least £5,000 per pupil next year while all primary schools will get a minimum of at least £4,000 from 2021-22 – with the biggest increases going to the schools that need it most.
"The IFS has said that this investment will restore schools’ funding to previous levels in real terms per pupil by 2022-23.”