South Essex is considered secure from a major flood disaster for the next 1,000 years, despite the threat of climate change.

The Strategic Flood Risk Assessment, commissioned by Thames Gateway South East Partnership, revealed that the effects of even a large breach in the seawall defences would fall short of catastrophe.

The survey was initiated by the five south Essex local authorities most at risk.

It used technology not available even three years ago to give an objective picture of a flood-hit Thames and the consequences.

Under the management of the Environment Agency, the survey used software to map the effects of breaches in various locations, using "digital water".

Changes caused by global warming were factored in to create a more realistic picture.

Essex county councillor Stephen Castle represents Rayleigh North but lives on Canvey.

He said: "I was interested in the report, not just as a politician but personally.

"My home is on the island, six-and-a-half feet below water level, and my business is also there.

"So my only interest was in an objective report.

"The report blows away the mystery and explodes the myths about flooding.

"It is very reassuring in terms of the effectiveness of the flood defences and the ability of the rescue services to respond in time and restore the defences very quickly, even in the worst case scenario.

"The reality is that even on Canvey, the water would be only a few inches deep after 24 hours and the breach would have been sealed within 24 hours."

The report was commissioned in the context of the requirement to build 43,800 new homes in the region during the next 14 years.

However, the report is merely advisory.

Jeremy Bloomfield of the Environment Agency, assessment project manager, emphasised: "It is not intended to advocate change or create policy. It is there as a source of accurate information for anyone who has an interest."

The availability of such precise information means that the onus will be shifted to would-be developers who seek to build in high-risk areas. Developers will have to prove second-level flood defences, specific to the site, are adequate - and pay for them.

Mary Spence, chief executive of Thames Gateway South Essex Partnership, concluded: "The SFRA is a piece of positive reassurance, a change from doom and gloom predictions about flooding."