Drink tap water to save the planet...

Thames Water and the Mayor of London launched a campaign today to promote tap water in restaurants and pubs.

The London On Tap scheme urges people to use less bottled water. It also plans a competition to design a recycled glass water carafe which can be used in restaurants across the capital.

"The message is very simple: don't be embarrassed to ask for tap water when you eat out," said Mayor Ken Livingstone. "You will save money and help save the planet. By drinking less bottled water, we can cut the climate change emissions coming from its production and transportation and cut the problem of disposing of used bottles."

A Panorama programme last night claimed government departments spent £1.3m on bottled water last year. Experts analysed the carbon footprint of a glass of water, finding London tap water used 0.3g of CO2, while Volvic used 185g and Evian 172g.

Environmentalists welcomed the campaign."Shipping water around in bottles is mad from an environmental point of view," said Friends of the Earth director Tony Juniper.