The greenest city on Earth

I've a confession to make as the Seoul Summit nears the end. I have become fiercely competitive on climate change. That's why - in an interview with a powerful American outlet - I made the bold prediction here that London will be the greenest city on earth by 2012.

That deadline is more important to me than other Mayors at this conference because that's when the world comes to London for the Olympics. It's clearly a tough target but I am - my friends - determined to do my best to meet it.

On stage today I encouraged every delegate to join us for the Games - and tried to tempt them with my dream of what they could see on arrival.

Stepping off the train at Paddington, I'd invite them to pedal onwards using one of the beautiful bikes available for hire every 150 metres in central London by next summer.

The roads should be easier as they ease onto a cycle super highway, breathing sweeter air as they pass cars generating no fumes and little noise. Thousands of trees, planted as we speak, will be filtering the air and casting cool shadows over the pavements.

The claustrophobic clutter will have gone, our urban realm subtly but strikingly more attractive. There'll be plants growing on roofs, railway sidings and canal boats. London's parks will have harvested the large investment now going into them.

London by then will be out of the global recession - helped by the new opportunities in the green economy, the City of London leading the world in green financial instruments.

Construction will have been helped by a massive programme of retrofitting homes. We don't want to be lagging behind on lagging. We'll be generating electricity from what is now considered waste. And our low carbon zones will pioneer the very best and latest in environmentally sound products and practices.

This sounds utopian, but it's well within grasp. But it won't come through warm words and communiques which is why my stubborn call - here in Seoul - is for real action to make this dream for many of us come true.