He told BBC's Newsnight the government appeared to be favouring an additional runway for Heathrow rather than his idea of a completely new airport in the Thames Estuary.

However, Johnson told the programme he would "die in a ditch" to prevent a third runway. Acknowledging it would take 15 to 20 years to build a totally new airport, he said expansion at Gatwick or Stansted would be a better "interim" solution to further expansion at Heathrow.

The government is due to publish a consultation paper on expanding airport capacity in the southeast and some ministers are known to be in favour of building additional runways to create employment and economic growth, although the coalition agreement rules out a third runway.

Johnson's plan, nicknamed Boris Island, would create a four-hub airport in the Thames Estuary, with twice the capacity of Heathrow.