London is not ready to deal with the increasing threat of flooding, according to a report.

A survey by the London Assembly discovered that no emergency services were legally bound by law to deal with floods, and monitoring of the drainage system was "patchy and incomplete".

The report, called 'Flooding in London' recommends urgent improvements to river defences along the Thames in Hammersmith, Chiswick and Twickenham in west London and a �4bn upgrading of the Thames Barrier after 2030.

But the Environment Agency disputes parts of the report and says much work is being done to minimise the risk of flooding.

Recent storms caused roads to flood

There will be more flooding from the Thames and its tributaries and London's drains will be overwhelmed by the expected increase in intense rainfall and storms, the report found.

And it says many tributary river flood defences, such as the River Lee in east London, are in a poor condition and must be upgraded by 2007.

But the Environment Agency says the river defences in west London do not need upgrading and those along the River Lee provide a high standard of protection.

The biggest threat is posed to London's drains, according to the report.

It reads: "The most serious risk is from a heavy rainstorm, which could generate as much as six inches of rain over 24 hours and overwhelm the drainage system.

"Because of the number of Londoners who live in basements, such a rainstorm could lead to a loss of life."

Flood risk

A full picture of the threat does not exist, because the drainage system is not the statutory responsibility of the Environment Agency.

Roger Evans, chairman of the flooding investigative committee, said: "There is no full map of London's drainage system.

"We need more detailed maps of flood risk areas and a better knowledge of our watercourses and drains."

The Environment Agency says it is working with Thames Water to look at the best ways of sharing information and improving ways of dealing with flood risk.