An online ad by Hildon Natural Mineral Water claiming bottled water is better for the environment than tap water was ridiculed by bloggers and on Twitter this week. The statement compares CO2 emissions, cleanliness and hormone content.

"You have to wonder if this is a hoax," said doctor and professional sceptic Ben Goldacre. And the National Hydration Council distanced itself from the ad. "Most bottled water is drunk as an alternative to soft drinks so that's the context for environmental comparisons," said director Jeremy Clarke.