As Patrick McLoughlin makes clear in his interview with The Spectator, Sir Howard Davies’s report on where in the south east new runways should be built will be published soon after the next election. The plan is that the new runways will then be approved and construction under way by 2020; meaning that there’ll be no chance for people to vote against them at a general election.
Strikingly, the Heathrow Hub option — which would extend the northern runway and then turn it into two runways — is rapidly gaining support in Westminster. Part of its attraction of is that the scheme would also enable you to extend the southern runway and turn that into two runways, creating — in effect — a four runway airport. Politically, there is also some appeal in avoiding simply building a third runway at Heathrow.
We’ll have to wait and see what Davies proposes. But I think the Heathrow Hub option is an increasingly likely one.