£20bn plan to halt London flooding

In an interview with The Sunday Telegraph, Environment Minister Phil Woolas said that a feasibility study into a second Thames Barrier would report within weeks.

Experts fear that by 2030, the existing barrier at Woolwich - which was built in 1983 - may no longer be able to cope with the increased flood threat due to climate change.

Mr Woolas said that ministers would need to take a decision on whether to go ahead with the new barrier "some time next year".

"When the Thames Barrier was built, it was built on the assumption that there was a one-in-2,000-year chance that London would flood. That estimate now is one in 1,000 years. In other words, from 1983 to today the probability has doubled," he said.

"This is no longer an academic debate. We have seen the floods in England and the extreme weather across the world. People accept that it is a real threat but they don't realise the imminence of it. Hopefully if there is any good that comes out of the floods it will be that recognition."

Mr Woolas said that a review of the flood defences at all major police, fire and power stations and other vital infrastructure sites was now under way, in the the wake of the summer floods across large swathes of England.

"The important question is whether the critical infrastructure sites have adequate defences. The protection they have is predominantly against terrorism and security assault," he said.

He said that the Government had come close to ordering the mass evacuation of parts of Gloucestershire last month after a crucial electricity sub-station was almost engulfed by the flood waters.

"It was one-and-a-half inches from flooding and had it flooded it would have been the biggest peace-time evacuation in this country in history," he said.