Plans to build the UK’s first deep coal mine in more than 30 years have been quashed.

At the High Court, judge Justice Holgate said environmental assumptions underpinning the development at Whitehaven in Cumbria were “legally flawed”.

The proposal by West Cumbria Mining (WCM) had received the go-ahead from the previous Conservative government in December 2022.

Victoria Marson from Friends of the Earth said campaigners had won “a massive victory”. WCM said it will “consider the implications” of the judgement before commenting further.

Legal challenges were submitted by Friends of the Earth and South Lakes Action on Climate Change (SLACC), who claimed permission for the mine did not take into consideration the environmental impact of burning coal, rather it focussed only on running the facility.

Lawyers for WCM said there had been “repeated mischaracterisation” of the plans and the development would have a “broadly neutral effect on the global release of greenhouse gas”.

In his judgement, Mr Justice Holgate said: “The assumption that the proposed mine would not produce a net increase in greenhouse gas emissions, or would be a net zero mine, is legally flawed.”

Duncan Pollard, a trustee at SLACC, said the ruling was a “huge relief”, adding: “We sincerely hope that any re-examination of the coal mine proposal considers all relevant issues and this ill-conceived idea is permanently shelved.

“Central and local government need to concentrate on secure and sustainable jobs for west Cumbria.”

Meanwhile Niall Toru, senior lawyer at Friends of the Earth, said: “The mine should never have been given permission in the first place.

“The case against it is overwhelming: it would have huge climate impacts, its coal isn’t needed and it harms the UK’s international reputation on climate.”

Mr Toru added Friday’s ruling could have international ramifications.

He said: “There are cases abroad where challenges are being made against fossil fuel projects on a very similar basis.”

This was echoed by Maggie Mason, from SLACC, who said: “This groundbreaking judgement could advance the global phase-out of fossil fuels. It is that big.

“Mr Justice Holgate has forensically destroyed their net zero, climate-neutral coal mine claims.”

At a previous hearing in July, the newly elected Labour government decided not to defend the decision to grant permission for the project, citing “an error in law”.

But WCM fought its case, arguing it could build a “unique” net zero mine.

In June, the Supreme Court similarly ruled that granting permission for an oil project in Horse Hill, Surrey, had been unlawful because it did not consider the emissions from burning the oil.