Johnson made the remark during a cheeky interview with New York magazine – the recently re-elected mayor has been spending some time promoting his new book about the history of London in the U.S.

“London is the most commercially important city in Europe, and it’s the most populous city,” said Johnson in the interview “It should be for the whole of the European continent what New York is to America. That’s what it should be.”

He then went on to mention his plans for a new airport (the Thames Estuary plan) and then dropped in a clanger that will almost certainly make David Cameron break out in a cold sweat – “One of the only reasons I want to assume supreme power in England is to make sure that happens…For God’s sake, don’t quote me saying that.”

Boris describes his new book Johnson’s Life of London: The People Who Made the City That Made the World as “a hymn of praise for London”.

Johnson will continue his time in the states with an appearance on Jon Stuart’s popular TV political chat show The Daily Show next week.