Villages on and near the north-east Norfolk coast might have to be moved elsewhere as sea levels rise, a leading conservationist has warned.The warning follows the news that homes and thousands of acres of farmland could be surrendered to the sea under a radical plan being considered by conservation bosses.

Villages on and near the north-east Norfolk coast might have to be moved elsewhere as sea levels rise, a leading conservationist has warned.

The warning follows the news that homes and thousands of acres of farmland could be surrendered to the sea under a radical plan being considered by conservation bosses.

At least six villages would be wiped off the map under the proposals which would involve the flooding of 25sq miles (6,500 hectares) of the Broads.

Under the plans the sea would be allowed to breach coastal defences between Horsey and Winterton, flooding low-lying areas as far inland as Potter Heigham and Stalham, where new sea walls would be built.

The area that would be affected is broadly the same as that which disappeared under water during the Horsey Floods of 1938, the most extensive floods in the area in living memory.

The villages of Eccles, Sea Palling, Waxham, Horsey, Hickling and Potter Heigham, as well as parts of Somerton, would be lost to the sea..

Commenting on the plan - Simon Hooton, director of conservation and countryside management at the Broads Authority, said: “We are facing some very significant challenges from climate change and we have to explore how we are going to adapt to those challenges.

“What the Broads Authority is doing with partners is discussing what those options are.

“Although at this stage we don't know whether settlements will need to be moved, as they have been in previous centuries, we may have to look at that.

“We have got to start looking longer-term at how we are going to manage it. In current thinking it would be too much - it would not be possible - but we have to put it in the context of previous villages that have been lost to the sea. How strong are we? How financially rich are we to stop that happening?”

Mr Hooton, among the delegates at last month's climate change conference at the Lansdowne Hotel, Norwich, said: “Moving a settlement has big implications but do you ignore it because it's too big? Whether it's the best thing or not, that's a long way off.

“Is holding the line the best use of our resources? I don't think there will be decisions for a very long time. We have got to look ahead and make some hard choices about investment now and in the future. Change is not necessarily a disaster if it is planned.”

A spokesman for Natural England, which organised the conference, said: “We're currently exploring the impacts of climate change on the Broads and the range of options to address these impacts.

“This research is still at an early stage although many of these impacts and ways of managing the change are already understood through shoreline management plans.

“Inevitably, some of these impacts are very significant but it is only by understanding these and gathering the best possible evidence that we can best decide how the natural environment and society need to prepare.”

A spokesman for Defra said: “The government is committed to sustainable protection for people and property - both inland and on the coast.

“That's why we have nearly doubled the spending on flood and coastal erosion risk management in cash terms, to an estimated £600m in 2007-08. Our investment over the next three years will total £2.15bn - with an £800m planned spend in 2010-11 alone.

“These record levels of investment are supported by a prioritised national programme of works to ensure tax-payer's money is used to best effect. We recognise the impact that the changing climate has on our coastline, which is why we are developing a range of approaches to help communities adapt to the changing coastline.

“From April 1, 2008 the Environ-ment Agency will have a strategic overview of all capital funding for coastal defence to ensure that works are appropriately prioritised, balancing national interests and local needs.”

Steve Hayman, project manager for the Environment Agency, said his organisation was committed to “hold the line” by maintaining existing sea defences for the next 50 years.

“In the medium-term we hold the line with a view to retreat to set-back positions through managed realignments when this is no longer sustainable,” he said. “The Environment Agency deals with the here and now as well as preparing for the future. It's going to get more difficult and expensive to hold the line but from the Environment Agency's perspective we're going to do our damnedest to maintain the defences in the best possible conditions because there are people living directly behind.”