The report funded by the Department for Communities and Local Government and the National Trust, tested "eco-homes" built to strict insulation standards up to 15% ahead of the latest building regulations and discovered unexpected massive heat losses.

The report 'Volume - Delivering Sustainable Housing' by the National Trust, Redrow Homes, Bryant Homes and Leeds Metropolitan University, studied 700 homes on a development on Trust land near Altrincham, Cheshire.

The tests carried out on the homes being built at Stamford Brook, once part of the Trust's Dunham Massey estate, revealed problems such as gaps between predicted energy conservation in the design and actual performance, with homes that were constructed to use 60% less energy than the average home in Britain, still leaking heat.

The lack of labour and environmentally sustainable products in the UK was also highlighted in the report.

Malcolm Bell, professor of Surveying and Sustainable Housing at Leeds Metropolitan University, who led the research team, said:

"If the Government's low carbon housing targets are to be achieved where it matters, on the ground, we must improve the whole production process and continually check that what we design in theory, is realised in practice.

This will require considerable effort not only in design and construction but also in education and training so that the lessons from research are continually fed back to the industry."

Rob Jarman from the National Trust added:

"A strong sense of direction from Government and wholehearted support from the construction industry is vital if we're to achieve the target that all new homes should be zero carbon by 2016. Action is needed to bridge the gap between the aspirations of policy-makers to create a greener housing stock and the reality of what is happening in the construction industry where the supply chain cannot deliver the volume of sustainable products needed."