A growing band of Labour MPs are joining a Heathrow rebellion led by the Keens, a survey has revealed.
Husband and wife duo Ann and Alan Keen, MPs for Brentford & Isleworth and Feltham & Heston respectively, have long opposed plans to expand the airport.
But research by a daily newspaper has revealed 18 Labour MPs across the capital have joined the 'no' camp amid fears the issue could cost them their seats at the next general election.
Greenpeace spokesman Ben Stewart said: "There is clearly a growing feeling of dissent on Labour's backbenches with London MPs realising that supporting a third runway is toxic for their electoral chances."
Airport operator BAA wants to increase capacity at Heathrow by up to 50 per cent and the government is due to announce the results of public consultation later this year.
Health minister Ann Keen has previously labelled the plans 'plane mad' and delivered a petition to the Department for Transport.