The decision of the Court of Appeal today is a historic victory in our fight to tackle the climate emergency. The world is facing a crisis and the UK has committed to achieving net-zero greenhouse gas emissions by 2050. That’s why this Conservative government’s obsession with building a third runway at Heathrow has always been opposed by the Liberal Democrats.

This year, Glasgow is hosting the COP26 climate change conference, and if we are to get meaningful commitments from other countries to cut their emissions, the UK must be seen to lead the world in climate action. Heathrow is already the UK’s biggest single source of carbon emissions. Expansion is projected to increase the number of flights by 300,000 a year and the number of passengers by 50 million, producing 4 million extra tons of CO2 emissions.

The government’s own advisory body the Committee on Climate Change has said the construction of the third runway “may break [the] government’s climate change laws.”

The village threatened by Heathrow's third runway Show all 4 1 /4 The village threatened by Heathrow's third runway The village threatened by Heathrow's third runway Heathrow's third runway expansion is threatening the village of Harmondsworth Simon Calder The village threatened by Heathrow's third runway Roy Barwick, a Harmondsworth Farmer, said: “To be threatened with eviction is a trauma second only to bereavement.” Simon Calder The village threatened by Heathrow's third runway Simon Calder Simon Calder The village threatened by Heathrow's third runway Resident Justine Bayley said: “The runway would be 100 yards from my front door.” Simon Calder

Aviation emissions in the UK have already doubled since 1990 and by 2050, aviation is expected to emit more CO2 than any other sector. To achieve net-zero, the Committee on Climate Change says that the aviation sector must grow by no more than 60 per cent compared with 2005. But the Tories have excluded aviation emissions from their commitment to achieving net-zero by 2050. This is simply unacceptable and, with a third runway, the target would be impossible.

When he was mayor of London, the prime minister pledged to “lie down” in front of the bulldozers if Heathrow’s runway went ahead. MPs approved Heathrow expansion back in June 2018, before the UK had adopted its net-zero target. That the Tory government seems set to reject this deeply damaging expansion is welcome news.

But the effect on the climate is not the only reason to reject Heathrow's third runway. As an MP representing southwest London, I am worried about the impact it would have on both air and noise pollution. Air pollution in London is estimated to contribute to 9,000 early deaths each year and over half a million people in the area surrounding Heathrow already suffer noise levels above World Health Organisation standards. The expansion will negatively affect both the health and wellbeing of thousands of Londoners.

Just a few weeks ago, Boris Johnson finally gave the go-ahead to the HS2 rail project, after months of speculation that it would be cancelled. At the time, he said that HS2 would help “level up” the country – and I agree with him. On Tuesday, the New Economics Foundation released a report saying that Heathrow would shift 27,000 jobs to London and the southeast from other regions, as well as £43bn of the nation’s income. If Johnson is committed to rebalancing the UK, now would be the time to speak out about the dangers of pressing ahead with the expansion, which is entirely at odds with his own promises to help regions outside of London.

The decision today has led to the Tories abandoning their challenge against the court ruling blocking a third runway at Heathrow. But it should also lead to Heathrow Airport backing away from appealing too. Expanding the country’s biggest airport will make it impossible to meet both our climate change commitments and to reduce the north-south divide. Of course, the pro-expansion lobbyists will be out again tomorrow, spending millions trying to convince Londoners that the quality of their air is not important and that the climate emergency is someone else's problem – it isn’t. The Liberal Democrats will continue to fight Heathrow expansion and for real action to stop the climate emergency.