The rest of the total would be built in urban areas and on what is known as "Brown Field" sites - land which is being reused after previous development, including former industrial sites.

The areas zoned for development would give a guide to planners and developers where new homes could be built. But the zones will depend on a review of the Green Belt and new homes could not be built without planning permission.

The overall plan must also be approved by Deputy Prime Minister John Prescott, who could alter the target figure for new homes.

Mike Roe, former Tory leader of North Somerset Council and currently chairman of the West of England Partnership, a body which represents the four councils in the former Avon area, said they realised growth was inevitable but were unhappy about the number of homes which will be permitted.

He said: "The councils feel they are being bounced into higher numbers than they feel comfortable with." Initially, the assembly was suggesting that the number of homes in the former Avon area should have been more than 100,000.

Mr Roe said it was with "huge reluctance" that the councils had accepted the 92,500 figure.

He warned: "This is subject to central Government coming up with the funding to provide the highway and public transport improvements which will be needed to cope with these extra homes." The fear is that the number of new homes will create widescale congestion unless there are major improvements to ease traffic delays.

The Evening Post revealed earlier this week that traffic delays in the Bristol area are costing the local economy an estimated ?350 million a year.

But it's only the Government that can provide the funding for major projects such as light rail systems, extensive showcase bus routes and investment in rail services, to ease congestion.

That's why the councils in the partnership have drawn up a Joint Local Transport Plan which shows what they believe is needed to help people travel around the sub-region without too many delays.

Mr Roe said the councils had agreed to a review of the Green Belt boundaries, but due to the numbers of new homes involved, it was inevitable that some of them would have to be built on existing Green Belt land.

He said: "It is absolutely essential that we sort out the funding for the infrastructure so we don't end up with horrendous congestion and we sort out the details of where the Green Belt should be." South Gloucestershire Lib Dem cabinet councillor Pat Hockey said:

"We are extremely unhappy about the number of homes which will have to be provided.

"It's inevitable that you cannot accommodate such a number without some encroachment of the Green Belt." Paul Crossley, Lib Dem council leader of Bath and North East Somerset, said: "We are not prepared to decide which Green Field sites are affected at this stage - that's the core of our argument with the assembly.

"We feel we must have the debate with the public about where the Green Belt should go and if any land is taken out, then we should be compensated elsewhere.

"The problem is that the Government is forcing change on us without allowing a proper debate about how that change should come. " Bristol's Labour leader Helen Holland said: "We need to get the Green Belt boundaries sorted out so they remain robust in the future."

The draft Regional Spatial Strategy says that as the urban areas will not be able to accommodate the amount of growth expected, then "well-planned urban extensions will be needed to meet this shortfall". In other words, it's inevitable that Bristol and, to a lesser extent, Weston-super-Mare and Bath, will expand.

The Government is expected to hold a public inquiry - known as an examination in public - before the spatial strategy is approved.

This might take several months because the RSS covers a region stretching from Devon and Cornwall to Gloucestershire and across to Swindon.

It could also result in Secretary of State John Prescott increasing the housing quota from the 92,500 level councils in the Bristol area say should be the absolute maximum.