Councillors from 26 authorities have signed a letter calling for more funding for disabled students before the shortfall reaches a “tipping point”.

With funding for special educational needs and disability (SEND) reaching a gap of £1.6billion by 2021, according to the Local Government Association, the councillors said London is particularly under strain.

The letter was signed by representatives from areas including Tower Hamlets, Barking and Dagenham, Newham and Redbridge.

It finishes with a call to "end the crisis in special educational needs and disability funding".

The cross-party effort was led by Tower Hamlets' member for children, schools and young people, Danny Hassell.

He said: "The funding we receive from government for special needs services is well below what we actually have to spend, leaving enormous budget gaps that local councils need to fill.

"The situation is completely unsustainable and the government cannot allow this crisis to continue. The children and young people who rely on these vital services need and deserve better."

While the letter was sent to education secretary Gavin Williamson before the government's announcement of £700million extra for SEND on August 31, Cllr Hassell said it wasn't enough.

"We welcome the recent announcement from the government about extra cash for special needs budgets, but the devil will be in the detail. I am concerned that this does not go the full way to closing the budget gap on high needs spending from last year - let alone what the gap is anticipated to be next year."

From 2016/17 to 2018/19, Tower Hamlets saw a 48 per cent increase in the number of children with an education health and care plan - a document that outlines what extra support a child needs.

Last year, the borough spent more than £56m on services while receiving only £49.7m from the government in SEND funding.

The mayor of Tower Hamlets, John Biggs, said: "Special needs provision faces a crisis across the country, a crisis which is hitting London particularly badly.

"The government is failing to fund SEND services properly and without immediate and urgent action the crisis will only get much worse, with serious implications for some of the most vulnerable children and young people in our society."

The Department for Education has been contacted for comment.