Stephen Byers would reject the plans

The policy has been included in a draft of the Exmoor National Park Authority's local plan, the blueprint for its planning policies.

But this would be rejected by Stephen Byers when he scrutinises the details, according to his department's spokesman.

He said: "The Secretary of State has powers to direct county councils and planning authorities.

"He has yet to comment on the draft plan but he reserves the right to use his powers of direction after consulting with the planning authority to change it."

He also said there is nothing on the statute books to enforce the policy.

"The law does not say anything about planning controls on second homes, so the government would have to draw up new legislation and there are no plans to do that," he said.

Other ministers however are said to be in favour of adopting a restrictive policy.

Ministerial support

Plaid Cymru MP Ellfyn Llwyd, whose constituency has seen an influx of second home owners, said Environment Minister Michael Meacher was "on board in principle".

Although other national parks have introduced measures to try to increase the amount of housing for local people, Exmoor is the first to suggest a policy deliberately targeting new second homes.

Exmoor's problem

Average house prices have risen 31% in three years Average wage 76% below the national average

Wages in the area are well below the national average, while Exmoor house prices have risen by a third in the past three years.

County planners have described the increase in the number of second homes as "alarming" - although the problem is shared by all Britain's national parks.

If Exmoor's radical housing policy were to go ahead, from the end of next year, buyers of all newly built homes would need to fulfil strict criteria, including residency in the local area for 10 years.

National Park Authority's principal planning officer Jack Ellerby said: "House prices within the national park are significantly higher than many parts of the region.

"The increasing gap between local incomes and house prices shows how important it is that we succeed in introducing new housing policies that will enable local people to continue to live within the area."

Michael Meacher: Said to be "on board" with plans

Although other national parks have introduced measures to try to increase the amount of housing for local people, Exmoor is the first to suggest a policy deliberately targeting new second homes.

The average house price in Exmoor, which lies on the Devon and Somerset border, is now �187,603 according to a recent survey.

The council's new local plan, due to go out to consultation next month, also suggests anyone wanting to occupy a property for less than six months of the year, will need to seek planning permission and where the number of second homes is already higher than 10%, applications will be refused.