Leeds schools could face cuts to their budgets of £15m - the equivalent of 380 teachers’ jobs being lost - because of rising staff and pension costs not being paid for by the Government.
The warning about changes coming into force over the next two years comes from a forum which represents 271 schools across the city.
The head of the Leeds Schools Forum say it could lead to significant financial difficulties for some schools, fewer teachers and larger class sizes.
Now it is planning to write to Education Secretary Nicky Morgan to highlight the problem.
The Government has vowed to protect the schools budget in 2015 and beyond but heads and governors warn that this will not cover extra staff costs coming into effect from this year.
Changes to public sector pensions mean schools employer contributions for teachers will increase from 14.1 per cent to 16.4 per cent from September.
The Leeds Schools Forum estimated this would mean £2.7m extra costs would have to be found from schools existing budget in 2015/16 and another £4.6m in 2016/17. Mr Agar who is also a governor at Horsforth Academy said: “At our school alone we are looking at an extra cost of £300,000. These are significant extra costs but there hasn’t been any pressure on the Government yet about this.”
The Leeds City Forum estimate the extra costs of pension and staff pay in 2015/16 will be £5.3m and by 2016/17 with increased National Insurance contributions also coming into effect the extra costs will be £15.5m.
Delia Martin and Steve Dixon the co-head teachers at Benton Park said that at large high schools like theirs it would result in a loss of more than a quarter of a million pounds.
“This is the equivalent of six teaching posts. If high schools had to lose six teachers this would inevitably mean larger class sizes and a reduction in the subjects which could be offered to students,” they said.
A Department for Education spokesman said: “Schools will have to contribute more towards pensions to ensure the costs can be met in future.
“We have delayed the increase by five months to September to give schools time to plan how they will meet the additional cost.”