Richmond, Merton, Kingston and Croydon councils have written to Prime Minister Theresa May in a bid to stop Heathrow expansion.

It has been widely speculated the Government will back the plans in the next two weeks, despite David Cameron, Mrs May’s predecessor, pledging ‘no ifs, no buts’ there would be no third runway.

The South London Partnership, chaired by Merton leader Stephen Alambritis, made the case to Mrs May for expanding Gatwick Airport instead.

It argued Gatwick would have lower environmental impacts, lower taxpayer costs and fewer legal barriers.

Cllr Alambritis said: “The South London Partnership boroughs stand ready to work with the Government, the Mayor, Gatwick and other partners to maximise the benefits of a new runway both in terms of stimulating additional economic growth in our area and by providing a skilled workforce to support other areas of growth.

“One thing in particular on which we want to contribute is ensuring the transport links to Gatwick and connectivity more widely, including into our area, central London and with other key corridors, are developed to support the full potential of airport expansion.

“Together with our neighbouring boroughs, we urge Ms May to make the right decision. Choose Gatwick.”

Conservative Richmond Council leader Lord True – who has also campaigned against Heathrow alongside Hillingdon and Wandsworth leaders – urged the Government to stand up for ordinary families, rather than ‘big business’.

He also pledged that Heathrow’s third runway would ‘never be built’.

Lord True said: “The Government should stick to its promise to rule out Heathrow, not pass the decision to Parliament.

“Government did the right thing in 2010 by scrapping Gordon Brown’s third runway folly and government should go for Gatwick now.

“We all know the Heathrow lobby can buy the best tables in town, but this is a government that has said it is for the ordinary family, the many, not the privileged big business few.

“If MPs vote to expand Heathrow it would spark a colossal backlash and a hail of legal challenges.

“Making Europe’s most polluting and worst located airport even bigger offends just about every environmental and security principle you can think of and will unite armies of campaigners in fierce opposition.”

Zac Goldsmith has repeated his threat to quit as Richmond Park MP if the Government approves the third runway at Heathrow.

Mr Goldsmith has previously said he would stand down as MP if Heathrow was allowed to expand, although he later told journalists he regretted that decision.

Mr Goldsmith told BBC Radio 4 on Friday that his position was ‘unchanged’.