Five councils have pledged to challenge parliament’s decision to back plans to expand Heathrow airport with a third runway.
The west London boroughs of Hillingdon, Hammersmith & Fulham, Richmond and Wandsworth are leading calls for a judicial review.
Further support will come from neighbouring Windsor & Maidenhead council, Prime Minister Theresa May’s own constituency.
The five councils have now formally notified the Department for Transport (DfT) of their intention to take legal action.
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In a joint letter, they say they will challenge the decision on the grounds of air quality, climate impact, noise pollution and access.
Councillor Ray Puddifoot, leader of Hillingdon council, said the government had been given “numerous opportunities” to alleviate the concerns of local people likely to be affected by the plans to expand Heathrow.
“They have demonstrably failed to do so,” said Cllr Puddifoot in the letter, adding the government had “misunderstood and misapplied” air quality law and stressing the impact on local communities made the decision be “untenable”.
Rival expansion group Heathrow Hub has already said it will take the decision to judicial review.
Mayor of London Sadiq Khan has also pledged to fight the decision, citing its failure to demonstrate how it will fund vital new infrastructure.
The DfT says it will “robustly” defend against any legal challenge and was confident in its decision to support Heathrow’s bid.