Such a move would be controversial because both coalition parties have committed themselves to oppose further expansion at Heathrow, Stansted and Gatwick.
According to the IoS, Chancellor George Osborne has now “refused to rule out Heathrow expansion because, allies say, it is key to Britain’s “hub status” for flights between Asia and the Americas.”
London’s business community has previously warned that ruling out additional runways at existing airports “can only undermine” the nation’s air strategy.
Any expansion at Heathrow would be an embarrassment for London Mayor Boris Johnson who only this month claimed he had “successfully opposed the 3rd runway expansion” at the airport.
Questioned by Labour London Assembly Member Murad Qureshi about aircraft noise complaints in Wandsworth, Johnson said:
“I recognise the important impact that exposure to noise has on the quality of life of many Londoners. That is why I successfully opposed the 3rd runway expansion of Heathrow, which would have extended the noise impact over a greater swathe of London”
Johnson added: “I have lobbied Government to consider options for new airport capacity which do not directly overfly London or other densely populated communities.”
The Mayor has spent much of his four-year term at City Hall championing an airport in the Thames Estuary despite opposition from local politicians and environmental campaigners.
The Thames Estuary is beyond London’s borders and City Hall has no power to construct airports.
In a recent interview with the Guardian Johnson appeared to distance himself from his own scheme, insisting he was “not the slightest bit wedded to some remote archipelago in the Thames estuary”.
The comments go further than remarks he made to the London Assembly in February.
Questioned by Liberal Democrat AM Caroline Pidgeon, Johnson said he wasn’t “wedded to a single location for a Thames Estuary Airport” but insisted “Locating a new hub airport serving London in or on the coastline of the Thames Estuary would offer a number of key advantages.”
Johnson previously told Pidgeon: “Any further expansion of Heathrow is unacceptable. If London is to retain its position as a leading World City and economic powerhouse, it needs a new hub airport.”
Earlier this month The Telegraph reported that the Government’s opposition to further capacity at Heathrow was preventing airlines from investing in expanding their operations.
On Sunday in a statement issued by his re-election campaign, Mr Johnson said: “Heathrow has a great future as a key UK airport. But we cannot endlessly expand it, and cram a quart into a pint pot.
“A third runway would be an environmental disaster. It would mean a huge increase in plans over London, and intolerable traffic and fumes in the west of the city – and it will not be built as long as I am Mayor of London.
“That is why the Government is right to look at all new solutions for extra aviation capacity except the third runway at Heathrow.”
Note: Mr Johnson’s statement was forwarded by a third party as his campaign declines to provide policy details and campaign announcements to this site.