Hundreds of Victorian school buildings are at risk under a Government policy that favours demolition over refurbishment, heritage campaigners say.
The buildings, many constructed in the early days of free education, are often structurally sound but need some work to fit them for modern needs.
Campaigners say they were built to higher standards than post-war schools but fear that they will be lost under the Building Schools for the Future programme, which aims to rebuild or renew every secondary school in England over the next 10 to 15 years.
The Victorian Society, a heritage charity, is holding a conference next month to discuss preserving the schools.
Kathryn Ferry, the society's senior architectural advisor, said: "We took this on as an issue because we were getting more and more telephone calls from people worried about their local schools being threatened with demolition."
The society has welcomed plans to spend £17.5 billion by 2008 on bringing school buildings up to date.
However, it is concerned that the allocation of funding - 50 per cent for demolition and new buildings, 35 per cent for major refurbishments and 15 per cent for minor refurbishments - plus lucrative private finance initiative contracts will be an incentive to replace schools. It argues that the money would be better spent on refurbishment.
Dr Ferry said: "If these schools had regular maintenance and there was a will and an incentive to refurbish them, they could last another 130 years.
"They are well-built, quality buildings with big windows, high ceilings, lots of ventilation and a light, airy environment for children."
The conference, called Learning from the Past: the Future of Historic School Buildings, aims to find imaginative ways of saving the historic buildings without compromising the needs of modern classrooms.
Delegates will hear speakers from the Department for Education and Skills, English Heritage and Institute of Education, among others.
English Heritage said there were nearly 6,000 listed school buildings or former school buildings in England. Many others were in conservation areas or were not listed but were of heritage significance or importance to their community. Thirteen per cent of school buildings were built before 1919, compared with nine per cent between the wars, 26 per cent between 1945 and 1966, 23 per cent between 1967 and 1976 and 24 per cent since 1976. Five per cent are temporary buildings.
In a document on preserving historic schools, English Heritage said: "Where it has been demonstrated that it is not possible to adapt an existing building for school use, we will normally favour conversion to a new use rather than demolition."
Bob Wallbridge, the assistant head of architecture at Hampshire county council, will speak about successes in his authority of refurbishing old school buildings.
He said: "I want to demonstrate the potential of older buildings. Older buildings do have a value to a community and that has to be weighed in the consultation process."
The DfES denied that it was intent on demolition.
"Our aim is to promote good design in all its forms, whether this is a new building or an adaptation, a spokesman said.
"We believe that buildings of historical or architectural interest should be retained where they can provide an inspiring and inclusive learning environment. Where this is not possible, the department shares English Heritage's view that alternative use should be found rather than demolishing the buildings."