The huge storms and powerful winds that have battered the coast of Britain in recent weeks have caused years' worth of erosion and damage, authorities said on Friday.

On some stretches of coast, the extreme weather has stripped away sand from stretches of beaches to reveal ancient forests, leaving the stumps of 6,000-year-old oaks protruding.

The National Trust, the body which manages much of Britain's most scenic coastline, said the storms have caused problems that it did not expect to have to deal with for years.

Cliffs have crumbled, beaches and sand dunes have been eroded, heavy seas have breached defences and shorelines and harbours have been damaged.

At Birling Gap on the Sussex coast, a popular tourist spot in southeast England, the speed of erosion has been "breathtaking", according to Jane Cecil, the National Trust general manager for the area.

"We've had about seven years of erosion in just two months. As a result of this loss of coastline, we are having to act now and take down the sun lounge and ice cream parlour, safeguarding the integrity of the rest of the building.

"We have to think long term," she said.

On the west coast Wales, the remains of oak trees dating back to the Bronze Age have been revealed as the sand has been stripped away.

The tree stumps on the beach between Borth and Ynyslas are said by some to be the origins of the legend of "Cantre'r Gwaelod", which according to myth was a kingdom now submerged under the waters of Cardigan Bay.

Meanwhile, as the mopping-up operation continues after widespread flooding in southwest and southeast England, a group of experts said the damage was preventable.

Some of the damage from the recent floods could have been prevented if the correct water management techniques had been used, they said.

The experts from 15 organisations urged Prime Minister David Cameron to convene a conference bringing together government departments and the embattled Environment Agency -- whose initial response to the floods drew heavy criticism -- to put in place measures to prevent a repeat of the floods.

The experts said sustainable drainage systems should be fitted on existing and new buildings and that buildings and land that cannot be properly protected should be made resilient to withstand flooding.

All new housing on flood plains should be resilient when built, they said.

In a sign of how the floods have re-shaped the political agenda, the main opposition Labour Party pledged that investment in flood defences would be a priority if it wins next year's general election.

The Met Office national weather service has said Britain suffered its wettest winter in records dating back more than a century.