Britain’s next prime minister must ensure schools which are “at financial breaking point” are given proper funding, an education conference has heard.

Parents and teachers gathered in Westminster at the Together for Education event in Central Hall on Saturday.

Among those to address the rally was Mayor of London Sadiq Khan, who said things must change for education funding under the next Tory leader.

He said: “Schools are at financial breaking point, teachers have been systematically undervalued, we have a great crisis in recruitment and retention, and teachers are having to spend their own money to ensure that children have the materials they need.”

Sharing what he described as “good news” with the audience, he declared: “The next prime minister will not be Michael Gove.”

The comment about Mr Gove, a former education secretary who was eliminated from the Conservative leadership contest earlier this week, was greeted with loud applause.

Mr Khan added: “My message to the next prime minister today is simple: enough is enough.

“This cannot continue. It’s time to give our education system and the next generation the investment they deserve.”

The Labour mayor is being joined at the event, where the next steps for a campaign against real-terms funding cut is also being planned, by his party leader Jeremy Corbyn, councillors, and trade unionists.

In his speech Mr Corbyn told the conference: “It’s the involvement of the entire community in supporting our schools and our teachers that can make sure we can put the pressure on this Government in the Autumn spending statement to re-fund the schools properly so that we don’t go into next year and yet another cut in spending per head within our schools.”

He said continuing an economic policy of austerity will lead to greater inequality, underfunding and “more and more underachievement” especially for those from the poorest backgrounds or with special needs.

Andrew Baisley, of the National Education Union, said school costs have risen by 7.5% in the last four years and that there are half a million more pupils than four years ago.

He said there is a £5.6 billion hole in education funding and that it is set to increase unless the Government changes its spending policy.

Speaking ahead of the rally, Kevin Courtney, joint general secretary of the National Education Union, said: “Schools have lost out on £5.4 billion since 2015, with 91% of schools suffering a per pupil funding cut.

“Further Education Colleges and Sixth Form Colleges have lost out even more.

“Promises to address school funding from Conservative Party leadership contestants, and rumours that the Prime Minister herself wants to give schools more money, demonstrates the cut-through power of this campaign despite the Government until this point consistently denying there is a problem.

“This conference will be addressing the ways headteachers, governors, MPs and parents can ensure we hold Government to account and get the money schools and colleges desperately need.”

A Department for Education spokeswoman said: “There is more money going into our schools than ever before, and since 2017 we have given every local authority more money for every five to 16-year-old in every school and made funding fairer across the country.

“In addition, we have provided more high needs funding for children and young people with special education needs and disabilities, an increase from £5 billion in 2013 to £6.3 billion in 2019-20, including an additional £250 million announced in December in response to local authorities’ and schools’ concerns about the rising costs of provision.

“We recognise the budgeting challenges schools face and have introduced a wide range of practical support to help schools and head teachers, to help schools make the most of every pound on non-staff costs.”