Writing in a column in The Telegraph, Howard Davies again reiterated his support for initial aviation capacity expansion in west London.

However, he went on to argue that should additional capacity still be required, Birmingham should be considered ahead of Gatwick.

He wrote: “The Airports Commission ran an open competition for the first new runway.

“The non-shortlisted airports, notably Birmingham and Stansted, accepted the decision, explicitly on the condition that they would be able to bid again for any second runway.

“Giving Gatwick the green light now would again risk a challenge, and might well turn out to be the wrong long-term decision. With HS2 in place, Birmingham might indeed be a more interesting option.”

Writing as a decision to expand Heathrow is expected on Tuesday, Davies also reiterated his support for the airport.

He said: “It is simply not possible to avoid adding new runway capacity near London if the city is to continue to prosper in a highly interconnected world, and decades of attempts to find new sites on which to do so have foundered.

“The arguments for making a decision now, and for Heathrow, have strengthened in recent months.

“Overseas, the lack of a decision is seen as a symbol of Britain’s inability to decide on its future as a trading nation.

“Gatwick is largely a European short-haul airport. It is also oriented towards outward tourism,” he added.

“About 70% of its tourist passengers are Brits going to the sun. Sadly, relatively few residents of Marbella and Corfu come here for their summer break.

“At Heathrow the tourist traffic is largely inbound. With our huge balance of payments deficit we need more high-spending American and Asian tourists to balance the books. And Heathrow has hugely more air freight, some 150 times as much as Gatwick by value.

“High-value exports go through the airport and its extensive infrastructure of logistics companies. Replicating that infrastructure around Gatwick would be hugely costly.

“So the case for Heathrow is overwhelming today. And as planes become quieter and less polluting it is possible to accompany expansion with a range of measures to make the airport a better and quieter neighbour, as the commission spelt out.

“Heathrow have accepted most of those recommendations, and there are many supporters of the airport in the area (as well of course as opponents). You struggle to find local supporters of expansion near Gatwick.

“The air quality problem, too, is capable of resolution. The pressure on the government, from the EU and our own Supreme Court, to make faster progress on a clean air strategy for London as a whole is helpful in reducing pollution in the area from other, non-airport related traffic.”

The decision build an additional airport is expected tomorrow although that does not mean everything will become plain sailing.

Newspapers reported over the weekend that some Tory MPs were preparing to back a legal challenge by four Conservative local councils should Heathrow be given the go-ahead.

Gatwick is also reported to be preparing a last-minute bid to derail such a decision with claims that it could build a second runway quicker and more easily.