Mayor converts to green envoy

Cripes! Boris Johnson, one of Britain's least environmentally friendly politicians, will this week relaunch himself as a green champion.

In his maiden green speech, which aides are billing as "extremely substantial" and "a milestone event", London's Mayor - who used to denounce "eco-moralists" for spouting "mumbo-jumbo" - is to announce his intention to make the city the eco-capital of the world.

The man who compared fear of global warming to a "Stone Age religion" has decided that he wants to make the capital "the world's leading city in delivering carbon reductions and capturing the benefits of the new energy economy".