But with billions of pounds already committed, officials have recognised that the rules do not sufficiently curb education’s carbon footprint.

Jim Knight, the schools minister, said separate carbon tests and off-setting schemes were being considered. “There is work going on to see how far down the road we can go in improving energy efficiency,” he said.

“A separate carbon test is a real option. The debate is around carbon emissions, so the temptation is to go down that road.” He said he expected to make a final announcement later in the year.

Schools bidding for money have to get one of two top marks under the Breeam test, a green assessment which measures them on eight counts: transport, water, pollution, building and management, health and well-being, material and waste, land use and ecology, and energy use. Mr Knight said the Government was considering making the tests tougher.

Mr Knight said the programme, which has been beset by delays, would focus on high quality design. But a report launched yesterday warned that buildings could end up unfit for purpose despite the huge level of investment.

The report, published by the British Council for School Environments (BCSE) and the British Educational Suppliers Association, listed almost 40 recommended changes to school design. It calls for greater participation by teachers and pupils, whose needs must be paramount.

Ty Goddard, director of the environment council, said: “School building investment opens the door to a fantastic opportunity to transform our education system. If we squander it, we risk ending up with new schools that won’t work.”

Tim Byles, chief executive of Partnerships for Schools, said: “We are resolutely focused on ensuring that Building Schools for the Future delivers 21st-century learning environments that inspire teachers to innovate.”

* Manifesto for Learning Environments: A Call to Action is available at www.bcse.uk.net