The capital's environment authority said that the melee of planning bodies with interests in the area has hampered the critical work of architects trying to maintain flood defence standards.
According to a new report, published yesterday (10 October) by the London Assembly Environment Committee, developers and architects are unsure of standards required and who to consult before submitting planning applications.
This, it says, is due to confusion surrounding overlapping masterplans and local development frameworks relevant to their work.
Darren Johnson, chair of the committee said: 'We are extremely concerned about development plans for east London and the building of thousands of new homes in the Thames Gateway.
'These plans are simply not taking the flood-risk issue seriously enough.'
In addition, the report stresses that for the majority of defences, the landowner is responsible for paying for and implementing maintenance. Yet in some cases, claims the London Assembly authority, it is impossible to identify who owns the land.
During the investigation, the committee was also told that 5 per cent of east London flood defences are in 'poor or very poor condition'. Information on those outside London, towards the coast, is also patchy, but defences are thought to be in a worse state than those in the capital.
The assembly claims that the area at risk from flooding in the Thames Estuary is currently home to 1.25 million people - more than the population of Birmingham - and is set to balloon over the coming years.
The Assembly's echo fears highlighted by Ricky Burdett, an architecture and design advisor to London's mayor.
Last month he told the AJ that the recent disaster caused by Hurricane Katrina in New Orleans should highlight the flooding risks facing the massive area earmarked for the capital's expansion (AJ+ 07.09.05).