The government's climate tsar has said a coal mine in Cumbria would never have been approved if his recommendations had been in place.
Chris Skidmore, a Tory MP and chairman of the government's net zero review, also expressed doubt over whether the coal mine would ever be built.
Speaking at the launch of his review, he said the decision, made by Michael Gove, the Communities and Levelling Up Secretary, in December "would not have been able to happen" if his recommendations had been in place.
The mine near Whitehaven, Cumbria, is the first new UK coal mine to be approved in 30 years and will be used to dig up coking coal for steel production.
Critics believe it would undermine climate targets and that demand for coking coal is declining, but supporters claim the mine will create jobs and reduce the need to import coal.
Its approval is now facing legal challenges, with Mr Skidmore adding: "Let's wait and see whether this coal mine actually happens - if this report is taken forward it never will."
On Friday, Friends of the Earth filed a legal challenge at the High Court over the government's decision to grant planning permission.
They called the decision "unthinkable" and said their challenge focuses on how Mr Gove "dealt with evidence relating to climate change" put forward by the group and others at the planning inquiry.
Rowan Smith, a solicitor at Leigh Day who is representing the environmental group, said: "Of particular importance in this legal challenge is whether the secretary of state lawfully concluded that the purchase of carbon credits would make a meaningful contribution to the UK's net zero targets, given their achievement relied on domestic - as opposed to international - offsetting.
"Friends of the Earth's legal claim has now been filed with the court.
"It is our hope that a hearing is granted to allow full argument on these matters."
The West Cumbria Mining project was initially approved in 2020 by the local county council but had to get final approval by the government.
Its approval was paused in early 2021 ahead of the COP26 climate conference after the government's climate change adviser said it would increase carbon emissions.
The Climate Change Committee (CCC), which advises the government, said 85% of the coal produced by the mine would be exported.
Lord Deben, chairman of the CCC, described the proposal as "absolutely indefensible" and said its approval would damage the UK's leadership on climate change.
The final decision was sent to Mr Gove, who ultimately approved it.
He said he was "satisfied that there is currently a UK and European market for the coal".
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