The mayor's suggestion in the summer heatwave of 2005 that Londoners saved water by flushing the toilet less frequently was considered an act of sacrifice too far for most people -- global warming or not.
Meanwhile, scientists from Nanyang Technological University in Singapore have invented a new toilet that turns human waste into electricity while reducing the amount of water needed for flushing by up to 90 percent.
Governments should encourage the capture of rainwater for use in washing and lavatory flushing, without the need for all water to achieve drinking water purity.
But Mr Mustow admitted that much more needed to be done to ensure that farmers did not increase flood risk with land drainage schemes and that developers and builders ensured that new developments allowed water to drain into the soil rather than flushing into the sewers.