The NUT, ATL, NAHT and GMB unions have asked every candidate running in the general election in England and Wales to promise to address “the largest school cuts for a generation”. 

The four unions’ have updated the Schools Cuts website so voters can email each candidate asking them to support more cash for schools to make up for a £3 billion shortfall which is expected by 2020. 

According to the unions, 99 per cent of England’s schools will lose out and the national average cut per pupil is £470. 

Their analysis shows that the consituency facing the biggest change in per pupil funding is Bermondsey and Old Southwark - a Labour/Liberal Democrat marginal seat where the change per pupil from 2015-16 to 2019-20 is £1,107.

Sixteen of the twenty constituencies facing the largest per pupil reductions are in London.

Kevin Courtney, general secretary of the NUT, said: “Parents, pupils and teachers are seeing the devastating effects of underfunding and the largest school cuts for a generation. No one ever voted for this.

“Every candidate in every constituency needs to be aware of these figures,” he added.

Mary Bousted, the ATL’s general secretary, urged all candidates to “pledge to invest properly in education and not divert funding to expensive free schools or selective education which only benefit a small minority of children”.

Russell Hobby, general secretary of the NAHT heads’ union, said the funding reductions “put the stability of the whole education system at risk”. 

And Tim Roache, general secretary of the GMB, said: “Our schools are being run into the ground and children’s life chances are being trampled over by this attack on education.”

This week’s Tes magazine features a funding cuts special, exploring the consequences of the cash shortfall being felt across the schools sector. It is on sale in all good newsagents. To download the digital edition, Android users can click here and iOS users can click here.