Birmingham's schools face financial ruin because of the city council's failure to plan for a new salary structure, it has been claimed.

Schools could be forced to pay millions of pounds to support staff such as teaching assistants or dinner ladies who claim they were underpaid for years, but the city council said it had no idea how much would be paid out.

Sandwell Council, which serves less than a third as many pupils, has told headteachers they can expect to lose up to £55 million from school budgets.

The chair of governors at one Birmingham school claimed the effect on city schools would be disastrous.

Mike Kelly, chair of governors at Hollywood School in Kings Heath, said: "We don't know exactly how much it is going to cost us.

"We need advice and support from the local authority, but we aren't getting it.

"But we have been receiving employment tribunal summons from staff who are claiming they were underpaid for the past three years and asking for £9,000 each.

"We can't afford a lot of claims like this. It makes it impossible for us to budget, and if a lot of claims like this come in then the school simply won't be able to afford to pay."

Those eligible for back pay include school support staff who have been systematically discriminated against in salary terms for years.

Their salaries are set to be increased as part of the "single status" reforms designed to end discrepancies which meant some local authority staff, mainly women, were paid less than others, mainly men, for doing work of equal value.

Local Government Employers, a body created by the Local Government Association to advise authorities about employment issues, has estimated that councils across the country will have to provide back pay of more than £1 billion, with a third of this going to school staff. Birmingham MP John Hemming (Lib Dem Yardley) has urged ministers to intervene and provide extra financial help to schools.

The MP has sponsored a Commons motion warning: "Schools face particular difficulties in handling the capital consequences of awarding back pay."

In September, the Government announced it was prepared to allow councils to borrow £500 million to meet the costs of introducing new salary structures, but the money would have to be paid back.

Coun Pauline Hinton, Sandwell's deputy leader and cabinet member for improvement and equality, said the "absolute worst case scenario" was that school staff would be paid £55 million in pack pay.

She said: "Whatever the settlement, the bill will still be significant and, in common with other councils, we will receive no financial help from the Government apart from a relaxation of the borrowing regulations."

Some of the money might come from other budgets but "we do need and expect schools to make a significant contribution", she said.

A spokesman for Birmingham City Council said schools were autonomous and responsible for their own staff.

He said: "Birmingham City Council has taken legal advice in relation to the position regarding the employment of staff at its maintained schools.

"This advice considers the effect of the School Staffing Regulations 2003 and the way in which Birmingham has granted autonomy to its community and controlled schools on employment and budgetary issues.

"As a result of that advice our position remains to be that each governing body is a single source responsible for the pay and conditions of staff employed at the school and is responsible for determining and settling all pay and single status issues with its staff.

"Foundation and voluntary-aided schools are also responsible for all employment issues relating to staff employed by their governing bodies.

"The city council is committed to supporting governing bodies through this process, and will continue to offer support and advice as appropriate."