LONDON // Two years ago, David Cameron mocked the idea of building a new, four-runway London airport on a man-made island in the Thames Estuary.
Yesterday, with congestion at Heathrow predicted to get much worse in the coming years, the government completed a remarkable about-face with Prime Minister Cameron's office confirming that the idea would be put out for consultation in March.
Fears that London could lose out to the likes of Frankfurt, Paris and Amsterdam as a major air hub appear to have convinced the government to take a serious look at what has become known as "Boris Island" after London Mayor Boris Johnson first proposed the idea.
Two years ago, Mr Cameron - then leader of the opposition Conservative Party - appeared scornful of the plan, grinning as he described the colourful Mr Johnson as "a great mayor of London doing an excellent job, but building airports is not his responsibility".
Mr Johnson persisted, however, and got architect Lord (Norman) Foster to design a £50 billion (DH281.7bn) airport off the north Kent coast, partially built on reclaimed land.
Now the government, which has ruled out building a third runway at Heathrow on environmental grounds, has given its firmest signal that it is having serious second thoughts about Boris Island.
"I genuinely believe that [ministers] see not just the overwhelming aviation argument," Mr Johnson told the BBC. "I also think the government understands the massive regeneration potential of this project.
"You can't go on expecting Britain to compete with France and Germany and other European countries when we simply can't supply the flights to these growth destinations - China, Latin America. We are now being left badly behind."
However, opposition to the idea of an airport in the estuary is formidable, not least from conservationists who point to the area's importance as a breeding ground for indigenous, endangered birds and as a winter stop-off for migratory species.
There is also considerable opposition from the Labour Party, unions, local residents and Kent's Tory MPs, as well as the Conservative-controlled Kent County Council, which is opposed to the idea because of the blight it and related infrastructure projects would bring to a primarily rural area.
However, big business and the airlines have long demanded increased airport capacity in London.
Andrew Haines, the chief executive of the Civil Aviation Authority, pointed out that not a single runway capable of handling a Boeing 747 or Airbus A380 had been built in SE England for more than 70 years.