A key water supplier is losing enough water to fill an Olympic swimming pool every five minutes as a ban on hosepipes engulfs householders in Kingston.

Thames Water loses 665m litres of water a day through leaks, according to industry regulator Ofwat.

The water company also hit customers with a 6.7per cent rise in bills, from April 1, four days before the hosepipe ban was imposed on Thursday, April 5.

A Thames Water spokesman said the company fixes 1,000 leaks a week from their 20,000mile network and leakage is down a third to the lowest level, since its peak in 2004.

The spokesman said:"We have hit our annual leakage-reduction target, agreed with Ofwat, for the past five years running and we are in line to hit a sixth by a margin of around 30m litres a day.

"However, we recognise that in some cases the speed we fix leaks isn’t good enough. We are continually working to improve."

The Environment Agency ordered water companies to do more to cut leaks after the organisation’s secretary Caroline Spelman’s announced that parts of south-east England were officially in drought.

With groundwater levels across parts of the Thames Water region close to the lowest levels ever recorded, many tributaries of the River Thames are running desperately low.

Under the terms of the Thames Water ban, customers can still water their gardens and clean their cars provided they use either a watering can or a bucket, not a hose.

There are exemptions for some commercial users, such as car washes and window cleaners, for the elderly and infirm, and for national and international sporting events.

Anyone found in breach of the ban could face prosecution.