Image copyright iStock Image caption Schools say increasing costs are putting them under huge financial pressure

Head teachers representing some 3,000 schools in England have written to their local MPs and ministers calling for a rethink on school finance plans.

They say a new national funding formula, which should give underfunded schools more cash, ignores inflationary cost pressures faced by all schools.

The heads come from 14 local council areas and represent 1.5 million pupils.

The letter comes as the government's consultation period for the new school funding formula closes on Wednesday.

The letter has been signed by primary, secondary and special school heads from a number of counties in England including West Sussex, Essex, Cambridgeshire, Norfolk, Suffolk, Devon and Cornwall.

The letter says the new funding formula does not offer "meaningful solutions" to current and future school finances and "attempts to ignore inflationary cost pressures that all schools are enduring".

"School leaders simply want a reasonable settlement that sees every child in every school adequately funded," it says.

The Department for Education said school spending was at record levels, but that the system for distributing that money was "unfair, opaque and outdated".

A DfE spokeswoman said: "We are going to end the historic postcode lottery in school funding and, under the proposed national schools funding formula, more than half of England's schools will receive a cash boost.

"We are consulting schools, governors, local authorities and parents to make sure we get this formula right, so that every pound of the investment we make in education has the greatest impact.

"We recognise that schools are facing cost pressures, which is why we will continue to provide support to help them use their funding in cost-effective ways, including improving the way they buy goods and services."

'We'll be £40,000 worse off'

Jules White, head teacher of Tanbridge House School in Horsham, West Sussex, has mobilised the campaign.

He told the BBC he had expected to be better off under the new funding arrangements, but has had a nasty shock.

"I was told I'd get £180,000 more with the new formula - which was very welcome.

Image caption Jules White says school leaders are speaking out out of necessity

"But then when I saw what I have to pay out from September - National Insurance costs, teachers' pay and running costs of the school, I found I'd be spending £220,000.

"So even with a new deal for the school - we'll be £40,000 worse off."

Mr White said school leaders cared deeply about their students and their families and were reluctant to speak out, but the fact that they were doing so showed the gravity of the situation.

"Why would we be doing this if it wasn't true? Why would I be telling you... that things are this bad unless I had to? And they are so bad, we're not sure we can cope going forward."

The head teachers' letter is also critical of the government's push to open more grammar and free schools in England.

It says: "To make matters worse - far worse - the Department for Education continues to divert significant monies to capital and revenue funding such as free school provision and grammar school expansion.

"At the same time, our schools simply do not have adequate funds to provide the education that every child in our care needs and deserves.

"To see such ill-judged spending being prioritised in a time of austerity is unacceptable.

"The disconnect between a department making decisions that seem to entirely ignore the wishes and needs of dedicated and committed school leaders provides significant and tangible cause for concern."

The consultation period on the funding formula ends on Wednesday, 22 March.