Insurers are pulling home insurance cover on flood-stricken Lewes, East Sussex. And many other areas are set to be hit when new rules for flood defence spending come into effect on 1 April.

Sources say Norwich Union, Direct Line, Royal & SunAlliance (R&SA) and Lloyd's syndicates are responsible for the price hikes or for pulling cover, a move denied by all.

And high-risk areas such as York, Worcester and Northampton could experience the same as Lewes when the Department of Environment and Rural Affairs (Defra) releases its priority points system next month.

Under the system, Defra's forward capital programme shows this year's priority projects must exceed the threshold of 22 points out of a maximum 44. In 2004/05, the threshold will fall to 15 points, then drop to 10 in 2005/2006.

David Crichton, author of Flood Risk and Insurance in England and Wales, said: "The points system is broken into three areas: 20 points for cost benefit, 12 for the type of people at risk (over 75, disabled, single mothers) and 12 for environmental issues (wetlands with unusual birds to protect, listed buildings or heritage sites).

National Flood Forum operations director Gill Holland said: "Deprived areas will take precedence over affluent ones and environmental considerations take precedence over people."

A Lewes Action Group survey showed 18% of households have been refused cover this year, 26% have seen "massive premium hikes", 37% have seen excess charges rise and 55% have seen no change. Around 250 homes and businesses responded to the survey.

With 13.8 points Lewes will not be allocated any flood defences for three years, putting a black mark on more than 800 homes and 150 businesses, because insurers will only insure if adequate defences are installed by 2007.

Peter Atkins of Lewes Flood Action Group said: "It's alarming that insurers have already started to pull cover or increase premiums."

In York, Clifton to Naburn Weir (scores no points) and South Esplanade (scores 5.9 points). This means they will not receive flood defences by 2007 making more than 250 properties uninsurable.

And Worcester - with 11 identified risk areas - scoring 3.8 out of 44 has fallen off the list indefinitely. Around 200 homes are at risk.

Worcester Action Against Flooding, said: "We are at the bottom of a very large pile as the Environment Agency has said no defences can be furthered along the river Severn as it is not economically viable to do so."

A spokesman for Direct Line said "We will continue to provide cover but may not take on new risks if flood defences are not put up. However, individuals may experience higher premiums or excesses depending on their circumstances.

A NU spokesman said: "Our technology enables us to map out individual cases and higher excesses or premiums may have to be added to maintain cover."

R&SA underwriting manager John Sawyer said: "We have to access individual risks but if areas are not receive flood barriers in place by the date set by the ABI, individuals could receive higher premiums or excesses or we won't be able to insure at all.

"The bigger the risk the more it will be reflected in the general rating of an area."