A legal challenge to block expansion of Heathrow has been launched by a group of councils, London mayor Sadiq Khan and Greenpeace.
The coalition formally notified Transport Secretary Chris Grayling of its intention to seek a judicial review of the Government’s decision to support a third runway at the west London hub.
Their letter sets out the grounds of their case and requests key documents.
The local authority group comprises five councils whose residents would be affected by expansion: Wandsworth, Hammersmith and Fulham, Richmond, Hillingdon and Windsor and Maidenhead.
They claim the Government’s National Policy Statement (NPS) setting out its support for the project fails to properly deal with the impact on air quality, climate change, noise and congestion.
Mr Khan said: “Heathrow expansion will result in hundreds of thousands of people being blighted by intolerable noise levels and worsening air quality in an area where pollution is already well above legal levels.
“The Government has failed to demonstrate how it will fund the billions of pounds needed to improve road and rail connections to the airport.
“I remain committed to opposing such a short-sighted decision which would have dire consequences for the health and quality of life of Londoners.”
Support from Labour MPs helped push through the proposals to expand Europe’s busiest airport with an overwhelming majority of 296 in a Commons’ vote last month.
Mr Grayling said the new runway would set a “clear path to our future as a global nation in the post-Brexit world”.
Construction could begin in 2021, with the third runway operational by 2026.