David Cameron is set to throw his support behind the once derided plan for a new airport in the Thames Estuary, it has been reported.
The scheme, initially proposed by the London Mayor and known as 'Boris Island', is seen as a alternative to the expansion of Heathrow. Plans for a third runway at the West London airport were shelved by the coalition when it came to power.
A formal consultation on the construction of a new international hub airport to the east of the capital is due to be launched in March to coincide with the publication of the government's aviation strategy.
According to the Daily Telegraph the prime minister will support a new airport but will withhold publicly backing the plan until after the consultation process is complete.
Boris Johnson said on Wednesday that he believed the prime minister and chancellor were "increasingly interested" in his proposal for a new airport. "I think that George and Dave understand the logic to alleviating the problem," he told the BBC's Today programme.
"You can't go on expecting Britain to compete with France and Germany when we simply can't supply the flights to these growth destinations; China, Latin America, we are being badly left behind," he said.
Osborne signaled he had warmed to the idea when he told MPs that the government would "explore all the options for maintaining the UK's aviation hub status" during his Autumn Statement .
Transport secretary Justine Greening, whose West London constituency is under the Heathrow flight path, was a vocal opponent of previous plans to build a third runway at that airport.
However the prime minister, chancellor and mayor may face a battle with the Liberal Democrats as well as local Tory MPs over the plan.
The Lib Dems opposed any airport expansion in the South East of England in their manifesto. "We opposed any airport expansion in the South East and we have opposed 'Boris Island' as well," a spokesman said.
The plan is also not popular with some local MPs, including Tory MP Tracy Crouch who said a consultation on a "Boris Airport" would be a "tedious, unnecessary, expensive waste of taxpayer money".
Colin Matthews, chief executive of airport operator BAA, told Today that while he welcomed the consultation "an island airport is very long and very expensive, even if it's agreed it'll be decades away".