Thousands of homes across Sussex face a repeat of last year's flood chaos without a huge and sustained injection of Government funds.

An Environment Agency study revealed the main cause of the disaster was the failure of existing flood defences.

Robertsbridge, Uckfield and Lewes are among 100 areas across the South singled out in the report for urgent measures to prevent further flooding.

The "overtopping" of EA barriers left 800 homes and businesses in Lewes and 100 homes in Uckfield under water.

The study also revealed many of the homes deluged with water did not have any defences at all.

Chichester was battered by the floods and the city will still have to go through another winter without full flood protection.

The city will have a new £4 million defence scheme but it will not be up and running for another two years.

Traders in Bevendean in Brighton have also called for better protection against the flooding.

Dams that were put up to stop the floods were found to be too small and in the wrong place. The dams were erected more than 20 years ago after severe flooding in the area.

Brighton and Hove City Council set up a scrutiny panel to investigate flood defences in the area following anger from traders.

The latest study was commissioned by Countryside Minister Elliot Morley. He is calling for the Government to make hundreds of millions of pounds of extra funding available to try to reduce the threat of a repeat.

Sir John Harman, chairman of the Environment Agency, welcomed the Government's acceptance that an extra £100m a year needs to be spent on flood defences. But he said more needs to be done.

The report criticised underfunding, neglect and continuing development on flood plains.

Sir John siad: "Years of underfunding in capital development, neglect of maintenance programmes and the continued practice of developing properties in areas of known flood risk has left too many people at risk from flooding.

"While we welcome the Government's injection of funds there is a real need for sustained long-term investment to ensure flood defences help minimise the risk to people of further flooding."

A more detailed report on the floods in Sussex will be published on March 30.

Last October's floods followed the highest levels of rainfall since records began 270 years ago, and the report warned climate change could make such extreme flooding more frequent.

The Government has revealed it could take up to a year to prepare a flood defence improvement scheme for Lewes.

In a written Parliamentary answer to Norman Baker MP, Mr Morley said the agency was just starting work on a study of the River Ouse and its tributaries.

He added: "It is expected the strategy, which will seek to identify sustainable options for flood defence in the catchment, will take eight to 12 months to complete."