Parts of Sussex may now never be developed following tough new planning guidelines issued by the Government yesterday.

The new rules tell developers and councils not to build in areas where there is a high flood risk.

The announcement follows a widespread rethink of planning procedures after autumn floods hit Sussex and low-lying areas of Britain.

In Sussex it will have an impact on new building in the Arun, Ouse, Cuckmere, Adur and Rother Valleys.

There will also be implications for any future development close to river mouths and areas exposed to the sea.

The 'don't build on flood plains' warning from the Environment Department followed autumn's disastrous floods, which left hundreds of people temporarily homeless and caused thousands of pounds of damage.

East Sussex, West Sussex and Lewes councils had all contributed to the debate on what should be done about future building in areas at risk from flooding.

However, Lewes Council warned MPs that too tough regulations could blight parts of Lewes and Newhaven.

It has identified several brownfield sites on flood plains which could be developed, bringing much needed jobs north of Newhaven.

Planning director Lindsay Frost said: "We do not want to see areas in Lewes with planning blight, which could be a bar to development."

The main changes to the previous draft mean local authorities and builders must look at lower-risk sites first.

A spokeswoman for the Environment Agency said: "These new rules will change the way councils look at planning applications and bring flooding back to the top of the agenda."

Environment minister Nick Raynsford told MPs: "The experience of the past few months has demonstrated the costs to all parties of development being located in vulnerable areas.

"Flood risk has to be taken more seriously, particularly since climate change is likely to increase the scale and frequency of flooding in the future."

The Government's action, however, was described as closing the stable door after the horse had bolted by shadow environment secretary Archie Norman.

He said: "Just issuing new planning regulations will not solve the problem of flooding - we need a more holistic approach."