£50bn ‘Boris Island’ airport plans step closer

The study, to be carried out in March, will consider several options but London Mayor Boris Johnson said the Government is “increasingly interested” in proposals to build an airport on the Isle of Grain in Kent.

Plans have been drawn up by Lord Foster for a 24-hour, four-runway airport built on reclaimed land capable of handling 150m passengers a year.

Prime Minister David Cameron has ruled out building a third runway at Heathrow Airport as an alternative, but the Liberal Democrats are believed to oppose the estuary idea.

Mr Johnson said: “I think that where we are is that the Government is increasingly interested in this idea.

“I genuinely believe that they see not just the overwhelming aviation argument and the argument from international competitiveness in making sure Britain has a hub airport that is viable for the long-term future.”

Colin Matthews, chief executive of airports operator BAA, said an island hub was “very expensive” and “decades away,” adding it would almost certainly cause the closure of Heathrow, with the loss of 100,000 jobs.

Labour joined Unions and environmentalists in condemning the estuary idea.

Shadow Transport Secretary Maria Eagle said: “If it is true that David Cameron is now willing to consider a new London airport then it would be an incredible U-turn from his pre-election position.”