Anti-Heathrow expansion campaigners have been given the go-ahead to challenge a High Court ruling over controversial plans for a third runway.
A group of councils, residents, environmental charities and London mayor Sadiq Khan brought four separate judicial reviews of the Government's decision to approve the proposals.
During a two-week hearing in March, they argued the plans would effectively create a "new airport" with the capacity of Gatwick and have "severe" consequences for Londoners.
Their cases were dismissed by two leading judges in May, but the campaigners were on Monday given the go-ahead to challenge that ruling.
Lord Justice Lindblom granted permission for a four-day hearing at the Court of Appeal in London, which will begin on October 21.
Giving reasons for his decision, which he made based on case documents without a hearing, the judge said: "The importance of the issues raised in these and the related proceedings is obvious."
The High Court case was brought against Transport Secretary Chris Grayling by local authorities and residents in London affected by the expansion, and charities including Greenpeace, Friends Of The Earth and Plan B.
The campaigners claimed the Government's National Policy Statement (NPS) setting out its support for the project failed to properly deal with the impact on air quality, climate change, noise and congestion.
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 in June last year.
Mr Grayling said at the time that 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.
