by Alan McGuinness

Boris Johnson has said he wants to “assume supreme power in England” to make sure an airport in Medway happens.

The London Mayor has long championed an airport in the Thames Estuary, and the government is to begin a consultation on the idea next month.

Three sites have been proposed so far: Grain, Cliffe and on two floating islands in the estuary, dubbed “Boris Island” after the Mayor.

A final decision is due to be made by March 2013.

Mr Johnson told an American magazine during a tour of New York: “We have to have a new airport. One of the only reasons I want to assume supreme power in England is to make sure that happens.”

He added: “For God’s sake, don’t quote me saying that.”

The former journalist and MP has been talked about as a future leader of the Conservative Party and perhaps even a potential Prime Minister.

In other comments this week, Mr Johnson claimed building another runway at Stansted would act as a short-term fix before an airport in the Towns.

A Thames Estuary airport could take up to 15 years to build, although some claim it could be done in around six.

Mr Johnson said: “A lot of money is now moving on to Stansted and the possibility of a high-speed rail link up there. You could be just as fast, if not faster, than at Heathrow.

”I think it is time that we looked at all the options around London because the Heathrow option is politically undeliverable and would be an environmental disaster.

“Increasingly people are thinking about Stansted as an option. You could get there quickly if Crossrail [a railway link being built around London] was extended.”

Prime Minister David Cameron has hinted that the government is willing to consider building a third runway at Heathrow, a prospect Mr Johnson said last month he would “die in a ditch” to prevent.