Schools face “catastrophe” because of a series of looming unfunded staff pay rises, heads’ leaders have warned.

They fear many schools are unprepared for an imminent large pay increase for support staff, which they say could result in job losses as schools struggle to find money to fund the rise.

In December the National Joint Council, which determines wages for support staff in many state-funded schools, set out its pay offer for the next two years.

The “bottom loaded” offer is aimed at giving the lowest paid staff the biggest increase - if the deal is accepted by unions, some staff will see their salary rise by 16 per cent over the two-year period.

However, the government has not indicated it will provide any extra money for the rise, meaning schools will have to pay for it out of their already stretched budgets.

Headteacher unions fear the only way schools will be able to fund the increase is by cutting staff levels.

Malcolm Trobe, deputy general of the Association of School and College Leaders, said: “School support staff do a fantastic job and deserve a decent pay rise. What is unreasonable is that the government expects schools to foot the bill for that pay rise without providing them with the funding to do so.”

“School funding is on the rocks at the moment,” he added. “When you’re already completely at the edge, this is a huge amount of money.”

Valentine Mulholland, head of policy at the NAHT headteachers’ union, said the lack of new funding would put budgets under “enormous pressure” and schools would struggle to find money to pay for the rise.

“When you’ve already pared down your support staff to the bone, there’s not very much more you can do,” she said.

The pay offer will impact many academies as well as local authority schools - union recognition agreements, combined with the fact that terms and conditions are protected when support staff have their contracts transferred from local authority employment, means many trusts abide by any NJC deal.

Martyn Oliver, chief executive of Outwood Grange Academies Trust, which runs 22 schools in the North East, Yorkshire and the East Midlands, told Tes that if the offer is enacted, it will cost his trust “a million pounds more a year for my existing support staff”.

A spokesman for Ark, where 21 per cent of support staff are subject to the NJC, said: “While we strongly support efforts to bring school support staff up to the real living wage, it is not possible to continue with pay rises in schools without a commensurate increase in real-terms funding.”

A Department for Education spokeswoman said: “The department is not involved in the process for setting support staff pay. We are aware of the offer and we will continue to support schools in managing their budgets.”

The funding pressure is unlikely to end with support staff. The lifting of the 1 per cent public sector pay cap means teachers are likely to be recommended a bigger pay rise later this year. And if, as many expect, that too is unfunded, Mr Trobe said it would be “absolutely catastrophic”.

“There is no way that schools can afford to pay any more out on pay rises, for teachers or support staff, without that being fully funded,” he said.

Mr Oliver said an unfunded pay award for teachers would result in “a dreadful situation in schools”.

This is an edited article from the 19 January edition of Tes. Subscribers can read the full article here. This week’s Tes magazine is available in all good newsagents. To download the digital edition, Android users can click here and iOS users can click here.