The controversial call came as the London mayor unveiled his preferred three plans for boosting the UK’s airport capacity.

Johnson said anyone in favour of expanding Heathrow was “crackers” and said it should be bought with £15bn of public money and turned into a 250,000-home estate.

Johnson’s plans include a four-runway hub on an artificial island in the Thames Estuary, previously dubbed Boris Island.

He also proposed a hub on the Isle of Grain in Kent or expanding Stansted Airport.

Johnson said: “Ambitious cities all over the world are already stealing a march on us and putting themselves in a position to eat London’s breakfast, lunch and dinner by constructing mega airports that plug them directly into the global supply chains that we need to be part of.

“Those cities have moved heaven and earth to locate their airports away from their major centres of population, in areas where they have been able to build airports with four runways or more.

“For London and the wider UK to remain competitive we have to build an airport capable of emulating that scale of growth.

“Anyone who believes there would be the space to do that at Heathrow, which already blights the lives of hundreds of thousands of Londoners, is quite simply crackers.”

A Heathrow spokesman said: “It seems extraordinary that any Mayor of London would propose forcibly buying and then closing Heathrow.

“The Mayor’s proposals would leave 114,000 people facing redundancy, cost taxpayers more and take longer to deliver than building on the strength we already have at Heathrow.”