Boris Johnson wants to be the 'greenest' mayor possible and encourage people to be more environmentally friendly.

The Conservative candidate pledged to champion cycling as well as walking and the use of public transport, if he becomes London mayor.

In an exclusive interview with yourlocalguardian.co.uk, he also said he agreed in principle with the congestion charge introduced by current mayor and Labour candidate, Ken Livingstone.

"Most people would agree that the congestion charge, although it does not work well at the moment and the money raised isn't being spent on the roads as it should be, was a good thing to do."

Speaking at yourlocalguardian.co.uk's Sutton offices this afternoon and answering questions posed by readers on the site, Boris said he wants to be "a very green mayor, the most environmentally friendly mayor possible."

"People want to be green. I do think there is a huge amount of difference we can make and we should do it," he said.

Boris also said the Tube needed modernising and that he would like to see a new tram going through south London from Croydon, through to Kingston.

"There is an economic powerhouse in south London and I think we could improve life for people if we could get them moving west to east and east to west more easily."