The Association of British Insurers has said up to one third of the extra 200,000 homes to be built in south-east England by 2016 were to be located in a floodplain.

And 10,000 of them could be located in areas of significant flood risk and thus be uninsurable for flood damage, said surveyors, unless rigorous planning controls and financial investment in infrastructure were put in place at an early stage.

The ABI report shows that a strong planning policy, fully implemented by local authorities and developers, could reduce flood risks to negligible levels in Ashford, the M11 corridor and the South Midlands, and by half in Thames Gateway.

Nick Starling, the ABI’s Director of General Insurance, said: “The government’s plans for a step-change in housing supply are essential to the economic and social well-being of this country. But they present challenges. Our report shows that flood risk in the growth areas could be managed effectively by building on existing government policies and plans."

“We welcome steps that have already been taken, but these need to go further. Working together, government, local authorities, developers, and insurers can ensure that truly sustainable communities are achieved. Managing the flood risk properly will enable insurers to continue to offer competitively-priced flood insurance.”

But the Royal Institution of Chartered Surveyors (RICS) says the East of England Regional Assembly initially supported John Prescott's proposal on the condition that suitable infrastructure would be in place.

At the moment, the government has not made the money available, leaving it to the developers to take responsibility for the necessary infrastructure such as water systems and roads.

According to flooding specialist surveyor and RICS spokesman, David Brooks: "The main concern is the long-term flood risk. Flooding is a significant problem which will only increase over time with climate change, rising sea levels and global warming."

"Who will be responsible for the long-term maintenance of flood defence systems which will need reinforcing in a few years time? It is essential that these issues are resolved and the housing plan re-evaluated to take account of the risks before the government proceeds with its plan to build homes in areas at significant threat from flooding."