She said that the safeguarding of life would be the Government's over-riding priority - flood warning systems and urban defences would have first call on available funds. Low priority will be given to the defence of agricultural land from incursions by the sea.
Mrs Shephard said: 'Experience has shown that natural river and coastal processes should only be disrupted by the construction of defence works where life or important natural or man-made assets are at risk. Intervention at one point can cause problems elsewhere.'
The new policy will mean that defences are technically more effective and more environmentally sustainable, she said.
Previously, defences have been constructed which cause sand to accumulate in one place, with a nearby side-effect of sand depletion and increased erosion.
The chaos that coastal erosion can cause was graphically demonstrated in July when the Holbeck Hall Hotel slipped off a cliff at Scarborough, North Yorkshire. The slow rise in the sea level is causing extensive erosion along the east coast.
Under the new strategy, unveiled at a local government conference in Great Yarmouth, Norfolk, the Ministry of Agriculture, Fisheries and Food will co-ordinate work being carried out by government departments, local authorities and other agencies, at a cost of about pounds 300m a year.
The strategy was drawn up by the ministry and the Welsh Office. Mrs Shephard said: 'This has included the operating authorities, conservation bodies, landowning and farming interests, engineering and academic institutions, other government departments and representatives of industry.' It aims to encourage provision of costeffective flood warning systems and adequate coastal defence measures, and discourage inappropriate development in threatened areas.