The leaders of Richmond, Wandsworth and Hillingdon councils have written to the new transport secretary to threaten legal action if the Heathrow expansion is approved.

Following reports a decision could be made as early as September, Lord True and Ravi Govindia, as well as Hillingdon council leader Ray Puddifoot told Chris Grayling they would launch a ‘legal challenge’.

In their letter the three argue a Heathrow expansion would be a slower and more costly option, with Gatwick representing a ‘far better option on every level’.

Lord True said: “Heathrow expansion – in either the form of the new north-west runway or the extension of the existing northern runway – would be an environmental disaster for our communities.

“Under both scenarios the costs far outweigh the benefits and we urge the Government to dismiss the inflated and implausible case made by the slick PR promoters of these schemes.

“The Prime Minister has spoken of her concern to protect communities and listen to the concerns of ordinary people. I have no doubt she will be true to her word.”

Ravi Govindia said Wandsworth residents had lived with the threat of a Heathrow expansion for too long – as he appealed for a swift decision.

The aversion to a Heathrow expansion in west London is such that Richmond Park MP Zac Goldsmith threatened to resign in 2015 if it was given the green light.