Coastal defences that currently protect huge swathes of farm land, natural habitat and housing are to be moved inland, allowing the sea to flood into low-lying areas.
In some parts of the country, householders and land owners have been told they face spending millions of pounds of their own money to build and repair flood defences to try to protect their property.
Among the areas affected are Medmerry, a popular tourist destination, near Selsey, West Sussex, where 612 acres are to be surrendered to the encroaching sea, and East Head, another nearby beauty spot where residents have been told their homes will no longer be protected.
Along the Humber estuary, around 800 homes scattered along the shoreline are to be left at the mercy of the sea within the next 20 years. At the end of that period, a further 1,000 properties in the area will be allowed to flood, including parts of the villages of Kilnsea and Sunk Island. In East Sussex, 260 acres of the picturesque valley of Cuckmere Estuary will also be lost over the next 15 years.
The new strategies have been drawn up by the Environment Agency, the government body with national responsibility for flooding, as it cannot afford to maintain all of the country’s 2,500 miles of coastal defences in the face of rising sea levels.
Instead, officials are drawing up detailed plans for the entire coast of England and Wales to decide where protection can be withdrawn.
The controversial move, however, has threatened to leave thousands of houses and acres of farmland vulnerable to flooding or even permanently underwater within the next 20 years without any form of compensation.
In some areas, the Environment Agency has said that it will repair and maintain defences only if landowners and residents cover the costs themselves. Home owners could also build their own defences, provided they meet planning and environmental rules.
John Bunn, managing director of Bunn Leisure, a holiday cottage and caravan park owner in the Medmerry area, said they had been forced to spend £1.5 million on flood defences that were completed this year and are planning another £10 million of work over the next two years.
“Our mile of seafront is as much a part of our infrastructure as the facilities we offer and I’m passionate about preserving both.
“Chronic underinvestment in sea defences for more than a decade has put us in the position of having to take matters on ourselves.
“We cannot leave the country to shrink – if the Dutch had taken the same approach Holland would now be half the size.”
In Kilnsea, residents have already taken matters into their own hands and are maintaining the defences themselves after the Environment Agency refused to defend their village.
They raised £200,000 through Environment Agency grants and charities to build a new embankment to keep the water from the Humber estuary from spilling into their village.
Nearly two thirds of the country’s coastline is currently defended with shingle banks, sea walls and barriers that are maintained by the Environment Agency using taxpayers’ money. Some land, such as that owned by the Crown Estate, has privately-maintained defences.
The risk of flooding is due to increase over the next century as sea levels rise by up to three feet. But the Environment Agency cannot afford to build new defences and increase the height of existing infrastructure in all of the areas it covers.
Ministers have instead decided to allow the agency to pick and chose the areas it will defend, with priority being given to towns and areas with special historical or natural interest.
The National Trust is also to abandon some of the 180 miles of coastline under its control after taking the decision that it could no longer afford to hold back rising seas and prevent erosion.
Visitors to Studland beach, in Dorset, which is among the worst affected areas, last week demanded urgent action to save the nature spot after beach huts have had to be moved back three times in the past 25 years due to erosion.
The Government currently spends around £600 million a year on protecting against flooding and coastal erosion and this will increase to more than £800 million over the next three years.
But Alison Baptise, national coastal policy manager at the Environment Agency, said that despite the funding increase, the Environment Agency still needed to prioritise where it spent the money by taking a strategic look at the nation’s coastline as a whole.
“There are clearly some areas that are more difficult than others,” she said. “As the coast is dynamic – it has been changing for years and continues to change – we can’t do the same thing at the same place all the time. We need to adapt how we manage it.
“In some areas there are defences built there that we could keep building up but it is not sustainable economically or good for the environment. These are long term changes and are not going to happen suddenly.”
The policy of abandoning defences and not raising defences in other areas has enraged campaigners, who claim house prices in effected areas have plummeted as residents struggle to sell their properties.
Malcolm Kerby, from campaign group National Voice of Coastal Communities, said: “People buy houses behind flood defences in good faith and then the Environment Agency can choose to move or abandon those defences at no cost to themselves.
“People living in areas that are being abandoned are seeing the value of their homes plummeting and they can’t sell them. Why would anyone want to buy a house in an area that will be regularly flooded in 20 years?”
Story by Richard Gray, Science Correspondent in the Telegraph