Like Churchill, Sir Richard Dannatt, head of the British Army, is preparing to fight them on the beaches. He is not alone. The Norfolk landowner has been promised support from hundreds of angry villagers, appalled by official plans to flood a stretch of East Anglia's coastline, letting the sea roll into 25 square miles of the Norfolk Broads, drowning six villages, hundreds of homes and thousands of acres of prime farming land. All along the East Coast, local communities are preparing for conflict with the Environment Agency over its plans for “managed retreat” - surrendering low-lying lands to the encroaching sea. At an ever quicker pace, South-East England is sinking, and the agency, appalled at the cost of keeping the sea at bay, has decided it will no longer play Canute.

The sea has been ravaging eastern England for millennia. The little Suffolk village of Dunwich was once a thriving medieval port, until a succession of storms swept it away. Legend has it that the bells of its six lost churches can still be heard tolling beneath the waves. But the pace of erosion has quickened in the past 50 years. Winter storms batter the coast more often as climate change increases their frequency. Sea levels, rising by two millimetres a year, are projected to increase to about 15 millimetres by the end of the century. Coastal defences are crumbling and landslips have left houses tottering yards away from the brink of sandy Yorkshire cliffs.

The Environment Agency, which last month took over responsibility for 6,000 miles of coastline and 800 miles of coastal defences from local authorities, is also looking over a financial abyss. The Government has increased spending on flood defences to £2.15 billion over the next three years, but this sum - much of it for inland schemes - will fall far behind what is needed to protect all the coast as sea levels rise. Instead, the policy of draining the marshes, fortifying the seawalls and cultivating the newly created farmland has been thrown into sharp reverse. Wetlands are to be restored. Estuaries are to be allowed to flood. New coastal saltmarshes will absorb the storms, making winter floods less likely.

Already, such a retreat has begun. In the Blackwater estuary in Essex, the walls were deliberately holed in 2002, allowing the sea to reconquer marshlands drained and farmed for centuries. The return of wading birds, the nursery waters for herring, Dover sole and sea bass and the effectiveness of the new “soft defences” is seen as an ecological success. But must all more populated or cherished estuaries go the same way? Proposals to drown the pretty Cuckmere Haven in East Sussex or abandon the sea defences between the picturesque Suffolk town of Southwold and neighbouring Walberswick have aroused furious opposition, not only from local people but from influential friends of these beauty spots. Protecting the coast, as the Dutch have found over centuries, is a national undertaking. But should coastal communities be overruled if they oppose “managed retreat” and begin to build their own sea defences? In many areas a surrender to nature makes sense. But where anguished villagers have battled against the sea, local authorities still have a duty not to abandon them. The fight on the beaches has just begun.