The Supreme Court has breathed new life into plans for a third runway at Heathrow Airport.
The scheme was previously blocked by the Court of Appeal, who said the government’s airports strategy didn’t meet up-to-date UK climate targets.
But the Supreme Court has ruled the strategy was legitimately based on previous, less stringent, climate targets at the time it was agreed.
The firm behind Heathrow can now seek planning permission for the runway.
But it still faces major obstacles, including having to persuade a public enquiry of the case for expansion.
And if planning inspectors approve the scheme, the government will still have the final say.
Ministers have been advised by their Climate Change Committee that, in order to keep emissions down, Heathrow should only expand if regional airports contract.
This will pose a problem for a government that’s committed to improving infrastructure away from the South-East.
And a full application from Heathrow Airport may still be more than a year away as the airport re-assembles a planning team and strives to cope with Covid.
A Heathrow spokesman called the decision to lift the ban "the right result for the country".
"Only by expanding the UK's hub airport can we connect all of Britain to all of the growing markets of the world, helping to create hundreds of thousands of jobs in every nation and region of our country.
"Demand for aviation will recover from Covid-19, and the additional capacity at an expanded Heathrow will allow Britain as a sovereign nation to compete for trade and win against our rivals in France and Germany."
The business coalition Back Heathrow said it would boost the UK once it stops following EU trading rules on 31 December.
“It is a huge moment for the UK as it moves towards an uncertain Brexit, but now with the confidence that international trade could be boosted by additional capacity at the country’s only hub airport," said executive director Parmjit Dhanda.
“We believe this news reflects a unity of purpose between the highest court in the land and our parliament – which has already delivered a majority of 296 for sustainable expansion at Heathrow,” he added.
The ruling is a blow for campaigners who’ve been hounding the runway project in the courts because they say it breaches the government’s policy of removing almost all carbon emissions from the economy by 2050 – the so-called Net Zero commitment.
But environmentalists still plan to challenge every stage of the planning application in the courts – including at the European Court of Human Rights, where campaigners will argue that relying on outdated emissions targets is inconsistent with the right to life.
The old UK emissions strategy was based on the target of holding global temperature rise to 2C, whereas the latest government aim is a maximum temperature rise of 1.5C. This means emissions must be cut by more than previously thought.
On the back of the previous Appeal Court ruling in their favour, environmentalists have launched copy-cat legal actions against plans for other government projects that will fuel climate change.
These include the £27bn roads programme; expanding North Sea oil and gas; and a proposed Cumbria coal mine.
They fear the Supreme Court ruling signals that judges aren’t willing to hold the government’s feet to the fire on climate policy - as the Dutch Supreme Court did last year, when it ruled that the country’s failure to act urgently against climate change constituted a violation of human rights.
Similar cases are underway in several other nations where citizens want politicians to keep promises to tackle emissions.
The Supreme Court case was taken by Friends of the Earth in conjunction with a tiny NGO called Plan B.
Its founder Tim Crosland told BBC News: “This is a terrible verdict – the runway plan is in clear breach of climate change targets and it can’t be allowed to go ahead. I can’t imagine how the judges came to this decision.”
Paul McGuinness from the No 3rd Runway Coalition, said before the court ruling that a decision in favour of Heathrow wouldn’t change the underlying case against the proposed runway.
He argued: “Heathrow expansion can’t proceed. Putting aside investors' lack of appetite to find new money - even to maintain the airport as a going concern through the pandemic - expanding Heathrow no longer ticks any boxes.
“Since the Airports Commission recommended Heathrow expansion, five years ago, the world has changed and the assessments on noise, air quality and carbon have been exposed as inadequate.”
Prime Minister Boris Johnson is a long-term opponent of Heathrow expansion, and significantly, his government didn’t join the appeal against the previous Appeal Court verdict, which was made by Heathrow Airport plc.
A government spokesperson said before the verdict: “We have always been clear that Heathrow expansion is a private sector project which must meet strict criteria on air quality, noise and climate change, as well as being privately financed, affordable, and delivered in the best interest of consumers”.
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