Popular comprehensives could be closed because councils cannot afford to shut private finance initiative schools without incurring multi-million-pound compensation claims.
Leading public services experts told The TES that non-PFI schools will be sacrificed rather than poorly-performing or redundant PFIs covered by 25-year contracts .
Their warnings come as the Government prepares to double the amount spent on PFIs from pound;1.6 billion so far to pound;3.2bn.
At next week's Labour party conference Tony Blair is expected to renew his commitment to the private sector playing a greater role in education.
But already taxpayers in Brighton and Newcastle face huge bills if the two councils go ahead with threats to close local PFI schools. In Brighton, a council source says the potential penalty for closing the struggling East Brighton College of Media Arts could be pound;17 million.
More secondary schools may have to close as pupil rolls fall across the country. The number of children aged at least 15 in schools peaked in 1999 at 7,191,600 but fell to 7,168,400 this year. The downward trend is expected to continue until at least 2014, when the Department for Education and Skills estimates the school population will slip to 6,612,500.
Dexter Whitfield, director of the Centre for Public Services in Sheffield, said authorities were only now facing the harsh realities of entering into lengthy PFI deals.
"Who the hell can forecast whether particular schools will be needed in 25 years' time?" he said.
"Once you go down the PFI path you start to lose all flexibility with the schooling system. Education and learning starts to be dictated by profit and loss."
Dr Jean Shaoul, from Manchester university's school of accounting and finance, who has led research into PFI, said: "If there are falling rolls and a need to close a school it will be the non-PFI school that takes the hit."
PFI has expanded rapidly since New Labour came to power because local authorities are desperate to improve crumbling buildings. Latest figures reveal there are 59 PFI contracts covering 595 schools with a total capital value of pound;1.6bn. The DfES say a further pound;1.6bn for 36 PFI contracts - involving more than 600 schools - has been approved. Another 19 projects covering 260 schools have been prioritised.
David Hart, general secretary of the National Association of Head Teachers, said: "There is a danger that when the demographics of your area change you will be left with egg all over your face."
The DfES said PFI contracts had to be negotiated to allow for variation of pupil numbers. A spokeswoman said: "There are costs involved in closing any school. A PFI school will be either newly-built or refurbished and in the event of closure the council would be likely to seek an alternative use for the buildings."