Confusion over responsibility for flood defences and planning policy has left the Thames Gateway at severe risk, according to a report by the environment committee of the London assembly.

The study says too many agencies share responsibility for flood defence, and that it is sometimes impossible to identify the landowner responsible for erecting them.

Five per cent of east London’s defences are in poor or very poor condition, the report says.

Information on defences outside London is scarce but it is thought they are in an even poorer condition.

The report also criticised the number of bodies drawing up planning policy and strategies for the Thames Gateway as well as the degree of co-ordination between them. It claims developers and architects are unsure who to consult in advance of planning applications.

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 Thames Gateway. These plans are simply not taking the flood risk issue seriously enough.”