The prospect of thousands of homes being built on Oxford's Green Belt significantly in- creased this week with a Government-backed report urging a radical approach to meeting housing needs.

The Barker Report, commissioned by Chancellor Gordon Brown to speed up the planning system, calls for a review of Green Belt boundaries and urges the release of land in areas where house prices are highest.

The report, by the economist Kate Barker, will encourage those wanting to see the expansion of Oxford into the Green Belt, allowing thousands of homes to be built near Grenoble Road, Greater Leys. Ms Barker's report argues that Green Belt boundaries often lead to increased pollution, by forcing commuters to travel by cars, buses and trains to major centres of employment. Her views are at odds with Oxfordshire County Council's strategy, now enshrined in the South East Plan, which proposes most new homes built in Bicester, Didcot and Grove.

Oxford Preservation Trust director Debbie Dance, above, said: "In Oxford we have been having this debate about the Green Belt and building near Grenoble Road as part of the Oxfordshire Structure Plan review. And the conclusion was that there is no need to build on Oxford's Green Belt.

"This is now being debated again with the Examination in Public of the South East Plan. Once again we will be putting our case for protecting Oxford and its green setting."

Conservationists fear that Oxford, along with Cambridge and London, will now become one of the hot spot areas for development.

Andy Boddington, of the Campaign to Protect Rural England, said: "Oxford should treasure its Green Belt and not trash it. Barker is now suggesting that Green Belts should primarily be ecological and recreational reserves.

"We can expect Oxford's Green Belt to move ever outwards until it becomes valueless."

Keith Mitchell, leader of Oxfordshire County Council and chairman of the South East England Regional Assembly, said: "We have spent three years preparing the South East Plan and listening to interest groups. The Government cannot ignore the fact that the region knows best."

The Barker report says that business developers and communities face high costs because of a slow and bureaucratic planning system, with current restrictions hitting competition and choice at a time of great housing need.