Head teachers today spoke up to defend their bank balances against criticism that they were hoarding cash meant for pupils.

While official figures show some schools apparently sitting on six figure sums, and others overdrawn, they say there are a host of complex reasons why.

The schools with large 'carry over' sums all said the money was earmarked for projects including the replacement of computers and building work.

Schools with overspends pointed to factors outside their control, such as unanticipated drops in pupil numbers.

Each of Bradford's 208 schools gets a different annual budget, related to how many pupils they have, and extra cash for such things as serving deprived communities or having pupils with English as a second language.

Governors decide how to spend their budget, although in practice have limited freedom of manoeuvre as about 80 per cent goes on wages, set nationally.

Variations in the number of pupils on the roll can have a disastrous effect on schools and many complain that planning is made very difficult as they do not know the size of their budget from one year to the next.

A joint statement from Bradford Council and Education Bradford said: "When schools have a large surplus or deficit, then they are asked to produce a spending plan, so we can monitor more closely how they are dealing with their budgets.

"For those with a deficit, extra support is offered and a payment plan agreed with schools, to help them balance their books."

The biggest surplus, £952,233, is at Carlton Bolling College, Undercliffe, a school in special measures after an Ofsted inspection.

Acting head teacher Bill Wolge said most of it was insurance money which had only just arrived after a fire in January 2000.

That was earmarked for new computer equipment and £200,000 for a Government-backed behaviour improvement programme that would be spent on teachers' salaries and learning mentors.

All would be spent by April or August at the latest, he said.

"There is absolutely no question of the money just sitting there in the bank."

Joan Law, head at Laisterdyke High, which has a surplus of £811,025, said: "Three quarters of our carry over is committed to building work."

Chris Thompson, head at Oakbank, said his school's surplus of £625,891 was about ten per cent of his £6.5 million budget, rather than the recommended five per cent: "I can understand people looking, but we are not storing up money for a rainy day."

Ian Cox, head at Rhodesway, another school in special measures, faces a deficit of £669,635. He said: "We will try not to let the deficit get any worse, and aim to move out of deficit within a number of years."

Mike Charnock, head at Westwood Park Primary (deficit: £186,468) said it would take years to recover, as the school's annual budget was only £430,000. When the school moved during reorganisation, the expected number of pupils did not materialise, leaving the school short of cash. "We are having to go without things," he said.