Plans to build a third runway at Heathrow Airport are illegal, a court has ruled.
Campaigners including environmental groups and Mayor of London Sadiq Khan had appealed against plans to expand the west London airport, one of the busiest in the world. The proposed third runway would cost £14 billion, and have meant an extra 260,000 flights a year at Heathrow.
A Court of Appeal ruled today that the government's climate change commitments signed at the Paris Agreement were not taken into account when the runway was planned, making the plans illegal. The government has set a target of zero net emissions by 2050, something the increased aviation emissions from a new runway could make significantly more difficult.
Could a third runway at Heathrow Airport still go ahead?
The ruling doesn't mean a third runway definitely won't happen — an amended plan could be drawn up, taking into account today's findings, or the government could appeal today's decision at the Supreme Court.
It's also thought the ruling could set a legal precedent — it's the first in the world to be based on the Paris Agreement, signed by 195 nations in 2016 to deal with greenhouse gas emissions. It may pave the way for challenges against other similar projects around the world.
The expansion has been discussed for years, with spiralling costs one of the reasons it had been delayed.
Prime Minister Boris Johnson had been against the plans when he was a backbencher, famously saying "I will lie down with you in front of those bulldozers and stop the construction of that third runway." Recently he seemed to be going back on this promise, so it will be interesting to see how he and the rest of the government react to this ruling.