After decades of dodging and delays, we could have a decision on airport expansion within a month. Downing Street has made it known that the Prime Minister, who personally chairs the Cabinet’s aviation sub-committee, intends to make a decision by mid-October (though of course she may take the opportunity to comment on it in her conference speech), and it looks highly likely that Heathrow will get the nod.

Heathrow may not be ideally located, but it is where it is, and it would be an error to continue to allow dreams of perfection to block the urgent need for new airport capacity in the South East. It’s all very well floating visions of moving the whole airport lock, stock and barrel, but the nation is still running a sizeable deficit. Similarly, while Heathrow expansion faces local opposition so would any other site. Every time politicians opt for the easier option of delaying the inevitable row, they harm British businesses and pass up new economic opportunities. For all Cameron and Osborne’s talk of “the global race”, they havered for far too long on making a call that is essential to our ability to compete.

So even if the decision isn’t going to please everyone, it will at least be good to have a decision at all. For May, who came in for some flak over her delay to Hinkley Point, it will be an opportunity to act when her predecessors (Labour and Conservative) preferred to delay and to emphasise that she meant it when she talked of a “proper industrial strategy”.

The question is, what happens after the Government makes its mind up?

Politically, there’s the obvious benefit that the London mayoral election is now out of the way. And while Sadiq Khan is opposed to a third runway at Heathrow, one can imagine that the Government views it as less awkward to have a row with a Labour mayor rather than a Conservative one. A protracted battle with Khan could be uncomfortable – a protracted battle with Goldsmith would have been worse.

Speaking of Zac, let’s not forget that May will still have to win a Commons vote for expansion. Ministers have briefed the Financial Times that they have crunched the numbers and are confident of victory, but to do so they will have to overcome a likely Tory rebellion. Opponents in the Cabinet such as Boris Johnson and Justine Greening would ordinarily bound by collective responsibility, but May is reportedly planning a free vote to minimise the strife within her new administration. Goldsmith said last year that he regrets his pledge to trigger a by-election if Heathrow gets the green light, but still intends to go through with it.

Heathrow have played a clever political game in building support among MPs across the rest of the country – they have deployed the benefits of an improved hub to secure the support of various regional airports, and have signed up a lot of non-London MPs in the same way. Yesterday, they redoubled their efforts on that front, offering to introduce extra flights and discounts for domestic passengers even before any new runway is built, contingent on getting the go-ahead for the project. As a result of this campaign, they certainly have a sizeable base of support in Parliament, but given the slim majority and a Conservative free vote they will still need the backing of at least some Labour MPs to be sure of victory.

Fortunately for the airport, and the Prime Minister, Jeremy Corbyn has inadvertently ridden to the rescue. With John McDonnell (whose seat is in West London) bitterly opposing the scheme, the issue has become bound up in the ongoing civil war between the Parliamentary Labour Party and the Opposition’s leadership. Rebels in the PLP are reported to be planning a move to make support for Heathrow Labour’s official policy, even without Corbyn’s backing. As a result, the Labour leader is now uncertain as to whether to try to whip his MPs or accept a free vote to avoid further conflict.

If the Government does decide soon, and if the vote is won, then the political plaster would at last have been ripped off. It makes sense for a new Prime Minister to take that short-term pain early on in her first term – as Cameron discovered, delay only causes a Government to sink deeper into the mire. There could yet be more political discomfort to come as a result of approving the scheme when West London voters find more planes flying over their houses, but a new runway wouldn’t open until 2026. That is sufficiently distant that it feels manageable – or by then it could even be someone else’s problem.