Headteachers in Cumbria are having to cut staff as they struggle to cope with a squeeze on school budgets.

Increasing numbers say they are also shelving plans for urgent building maintenance, reducing support staff, increasing class sizes and not renewing IT equipment and books as they look to save money.

The warning has come from a leading teaching union official as he prepares to take school leaders' concerns to ministers.

Graham Frost, Cumbria branch secretary of the National Association of Headteachers, also says that schools are becoming more reliant on Parent Teacher Associations to raise money for essentials such as books.

Mr Frost, headteacher of Robert Ferguson Primary School in Denton Holme, Carlisle, revealed the measures leaders are increasingly taking to balance the books as he prepares to attend a meeting with schools minister Nick Gibb and the county's MPs on Tuesday.

It has been brokered by South Lakes MP Tim Farron.

The meeting comes as a new report by the Education Policy Institute suggests that the average secondary school in England is facing losses of almost £300,000.

The figure for an average primary is £74,000.

The EPI warns that growing financial pressures mean that schools are facing real-term reductions of between six and 11 per cent by 2019/20.

Education unions estimate that Cumbrian schools could lose £23m by 2020 - the equivalent of 625 teachers or an average of £383 per pupil.

The Government says investment in education is at a record high at over £40 billion and will rise before 2020.

Concerns are being raised as debate continues about how to best ensure existing funding is shared out fairly among all schools.

While campaigners battle for better funding, consultation on government plans to introduce a new National Funding Formula closes on Wednesday.

Mr Frost said: "NAHT have campaigned for and welcomed efforts to make the distribution of funding fairer.

"However, a combination of increasing costs to schools, the removal of the Education Maintenance Grant and reduction in funding to other services such as school nurses have resulted in school leaders having to make increasingly tough decisions about which staff, services, resources and building maintenance projects to prioritise and which may have to be axed."

He added that "resourceful" school leaders are working together to make savings.

"But with staffing costs at around 80 per cent of overall school expenditure, and the remainder consisting mostly of utility bills, essential services, with only the thinest end of the wedge being left for resources and building maintenance, it is proving increasingly challenging for schools to meet the government’s challenge for schools to “find efficiencies which will not impact on educational outcomes”", he added.

"On the basis of funding constraints, Cumbria’s school leaders are now reporting in increasing numbers that they are already compelled to take action."