Two schools have warned they are ready to take legal action unless a financial dispute blocking their aim to become academies is resolved.

Rokeby School and Lister Community School issued the stark warning to Newham Council accusing them of blocking their plan by demanding an extra £500,000 a year to cover the cost of the private finance initiative (PFI) deal struck to build both schools.

The schools, which state they already pay about £1m a year in PFI costs, claim the additional payment is not part of the original contract and any extra charge would jeopardise their plans to become academies and possibly lead to redundancies.

Lister, in St. Mary’s Road, Plaistow, and Rokeby, in Barking Road, Canning Town, have teamed up with Sarah Bonnell School in Deanery Road, Stratford, to form the Newham Community Schools Trust in an effort to advance their cause.

The trust’s chair, John Ainsworth, said: “We are astonished the council is looking to balance its books at our expense and is holding back our schools’ vision.

“Our only motivation in seeking these academy conversions is to provide Newham students with an even higher quality of education.

“It appears the council is leaving us with no choice but to pursue court action.”

The trust claims that earlier this year the Department of Education intervened, leading to the council’s director of children’s services, James Thomas, offering a compromise deal which was later withdrawn.

However, the council accuses the schools of misrepresentation. A spokeswoman did not accept the claim the council is using the schools to balance its books, but said the dispute is about what is due under the terms of an agreement already signed by the schools.

The council went on to accuse the Trust of misrepresenting Mr Thomas’s proposal, stating it was actually a clarification of the figures involved in the original deal.

The spokeswoman added: “We want to secure the best for all our pupils and are supportive of these schools forming a multi-academy trust as we believe it will help them drive up their standards.

“The council has sought to clarify the amount they owe under the PFI agreements their governing bodies signed. The council hopes that legal action can be avoided.”

Commenting on behalf of the NUT, Iain Hale said: “The problem is PFI. We’ve always had a concern about the money coming out of school budgets to pay contracts. It’s a flawed system.”