Teachers are turning to food banks to feed their families, shadow education secretary Angela Rayner has warned.
Her remarks were made at a rally held in Westminster today, where campaigners had gathered as part of a mass lobby of MPs over school funding.
Ms Rayner said: "It's an absolute tragedy that we have headteachers now having to run marathons where they used to run them for charity to give funds to their school."
"It's really devastating when we have letters going home to parents asking them to provide what the state should provide within our education system.
"It's disappointing that so many teachers have had to leave the profession because of the strain that they have been put under. It's disappointing you've had to write those letters to parents."
She added: "I've had letters from teachers in absolute despair that they have had to leave the profession because they can't even feed their own [children], they have had to use food banks and they can't feed their own families.”
Her comments on the plight of individual teachers come weeks after Liberal Democrat education spokesperson Layla Moran revealed a school in her constituency had asked a food bank for help to provide lunches.
Other speakers at a rally in support of today’s lobby, organised by the school cuts campaign, were Liberal Democrat leader Sir Vince Cable and shadow chancellor John McDonnell.
Sir Vince gave his party’s backing to the call for more funding. He said: “I am going to get behind your campaign to make sure schools get the resources they need and teachers get the pay they need.”
A Labour government would provide “education from cradle to grave, free at the point of need", according to Mr McDonnell. He said: “We need to join forces across Parliament. We cannot stand by and sell the future of our children.”
But schools minister Nick Gibb, responding to the demands for more funding, accused the National Education Union of making “misleading” claims and insisted “there are no cuts in funding”.
He added that “overall schools funding is being protected at a national level in real terms per pupil over the next two years” and highlighted the extra £1.3 billion for schools announced earlier this year.
Geoff Barton, general secretary of the Association of School and College Leaders, said: "We welcome the education secretary's commitment to a new formula to address the postcode lottery in school funding.
"But slicing up the cake more evenly cannot disguise the fact that the cake is not big enough in the first place."
While the £1.3 billion boost would protect real-terms per-pupil funding between 2017 and 2019, schools still face a 4.6 per cent cut between 2015 and 2019, because of inflation and rising pupil numbers, according to the Institute for Fiscal Studies.