Controversial plans for a third runway at Heathrow Airport have been thrown into doubt after a court ruling.
The government's decision to allow the expansion was unlawful because it did not take climate commitments into account, the Court of Appeal said.
Heathrow กลุ่มลับไลฟ์สด18+ said it would challenge the decision, but the government said it would not appeal.
The judges said that in future, a third runway could go ahead, as long as it fits with the UK's climate policy.
The case was brought by environmental groups, councils and the Mayor of London.
There were "whoops and jumps of jubilation from environmentalists outside the court room" after the judgement, environment analyst Roger Harrabin reported.
Transport Secretary Grant Shapps tweeted that the government would not appeal against the ruling.
In an interview, he said that it was "for Heathrow and the courts to decide" whether the expansion should go ahead.
"This government is absolutely committed [from] the Prime Minister down to airport expansion, but, we want to make sure that expansion is environmentally friendly," he said.
Heathrow chief executive John Holland-Kaye said the airport would challenge the court's decision at the Supreme Court, saying: "We think the appeals court got it wrong".
"We have a very strong legal case, and we will be making that very firmly," he said.
He said in the meantime Heathrow would work with government on a review of its policy "to make sure we can demonstrate expansion หลุดหลุ่มลับ is compatible with the Paris accord on climate change".
"I'm confident that this issue is fixable, and we can work with the government to get on and deliver the expanded Heathrow that Britain needs," Mr Holland-Kaye added. "Without Heathrow expansion, there will be no global Britain."
Friends of the Earth, one of the environmental groups that brought the case, said the ruling was "an absolutely groundbreaking result for climate justice".
Will Rundle, head of legal at the campaign group, said: "This judgment has exciting wider implications for keeping climate change at the heart of all planning decisions.
"It's time for developers and public authorities to be held to account when it comes to the climate impact of their damaging developments."
Greenpeace said the government needed to "permanently ground Heathrow's expansion plans".
Greenpeace UK's executive director, John Sauven, said: "The third runway is already on its knees over costs, noise, air pollution, habitat loss and lack of access, and now Heathrow has yet another impossibly high hurdle to clear.
"Boris Johnson should now put Heathrow out of its misery and cancel the third runway once and for all. No ifs, no buts, no lies, no U-turns."
MPs voted overwhelmingly to support Heathrow expansion in 2018, with Boris Johnson out of the country at the time.
Before he became prime minister, Mr Johnson pledged in 2015 to lie down "in front of those bulldozers and stop the building, stop the construction of that third runway" at Heathrow.