Thousands of people are deserting cities and heading for the Midland countryside, putting too much pressure on the environment, campaigners warned today.

Despite efforts to reverse the continuing exodus to rural areas, migration into the countryside has reached a record 12,500 a year, according to new figures.

The figures, released by the West Midlands Regional Assembly, show 5,000 people migrate to Staffordshire each year, 3,700 people move to Warwickshire and 3,400 to Worcestershire.

New Regional Planning Policies were implemented to reverse this trend but, although some urban authorities are deemed to be building enough houses, places like Dudley are not building enough and too many houses are being built in Warwickshire, the Campaign to Protect Rural England said.

Gerald Kells, regional policy officer for CPRE West Midlands, said: " This is an extremely worrying trend. If people continue to move out of our cities at this rate, the loss of countryside to housing could be catastrophic.

"We need to build the right housing in our cities to attract a mixed population and we need to ensure all the environmental and social building blocks of regeneration are in place. Simply carpeting the countryside with suburban housing is not going to create balanced communities."

The CPRE said proposed changes to planning rules could make matters worse.

If Government plans were introduced whereby housing levels had to respond to market price, the more people moved into the countryside the more houses would be built to accommodate them.

Mr Kells added: "If Government has its way we will end up in an Alice in Wonderland world. Because we're building the wrong houses in the wrong place, communities are becoming more and more unbalanced in the region.

"That makes house prices rise in desirable areas so we end up building more houses there and the situation gets even worse. This monitoring report should be a wake up call to local, regional and national politicians to work harder to protect our environment and support regeneration."

Earlier this month the CPRE warned that England could lose most of its countryside within a generation unless current trends are reversed.

The organisation claimed 21 square miles of countryside is lost to development every year.

A poll conducted by the CPRE to mark the 50th anniversary of the Government circular instructing councils to set up green belts found nine out of ten people in the Midlands wanted greater protection of the countryside against new housing and urban sprawl.

Local authorities across the Midlands are facing pressure from John Prescott, the Deputy Prime Minister, to address the housing shortage by building new homes in rural locations.

Mr Prescott outlined a long term plan to more than triple the size of Milton Keynes making it eventually a city larger than Birmingham.

Demographic changes, with people living longer and the rise of single-parent families, will continue to put pressure on a limited housing stock, according to Mr Prescott.

The West Midlands population increased by an estimated 90,000 to about 5.3 million between 1991 and 2003 - the latest year for which figures are available.