Climate groups are launching two separate legal challenges against Tory ministers to halt the decision to grant permission to drain fossil fuels from the UK’s largest untapped oilfield.

Uplift and Greenpeace UK are seeking to overturn the UK Government’s decision to allow development of Rosebank, the UK’s largest untapped North Sea oilfield.

The campaign groups have both applied to the Court of Session in Edinburgh for a judicial review of the decision by the Energy Secretary, currently Claire Coutinho, and the North Sea Transition Authority (NSTA), legally known as the Oil and Gas Authority, to grant consent to the project.

The groups will argue that the decision to grant permission is unlawful because it ignores the impact of emissions from burning Rosebank’s oil, it is not compatible with the UK Government’s plans to cut greenhouse gas emissions and achieve a safe climate, and it would damage a protected area of the North Sea and the diverse marine life it supports.

Read more: Revealed: Rishi Sunak's 'false' claim North Sea oil and gas cleaner than imports

Campaigners warn that Rosebank, 80 miles north-west of Shetland, contains around 500 million barrels of oil, which when burned would emit as much carbon dioxide as running 56 coal-fired power stations for a year.

Activists have also warned that the UK public will carry the vast majority of the costs of developing the field, with Rosebank’s owners set to receive around £3 billion in tax breaks.

Most of the oil extracted from Rosebank will be sold on the global market and exported and not used initially for domestic demand.

Tessa Khan, executive director of Uplift and a climate lawyer, said: "If Rosebank goes ahead, the UK will blow its own plans to stay within safe climate limits. It’s that simple.

“If the Government disagrees, it needs to provide evidence and prove it in court. The regulator also needs to be open about its reasons for approving a huge oil field when we’re facing a worsening climate crisis.

Read more: SNP Government urged to 'redouble efforts' to scale back fossil fuels

"People have had enough of oil and gas companies getting their way all the time. This case is about forcing our government to put the public’s safety first, over their need to profit.

"What’s clear from this year’s climate talks is that the UK government, like other oil producing countries, is failing to protect our world from dangerous climate change. But rather than lose hope, we can and will hold them to account, in court, starting with this decision to approve Rosebank."

Greenpeace UK’s co-executive director, Areeba Hamid, added: “Rosebank’s development was approved under the false claim that it is entirely compatible with the UK’s legally binding climate commitments. This is a lie.

“The Government used a rigged climate assessment to approve its development, deliberately ignoring all of the emissions that will come from burning the 500 million barrels of oil it contains. It’s like building a bomb and claiming it’s completely harmless so long as no one detonates it.

“Since its oil will be exported and sold by Norwegian fossil fuel giant, Equinor, Rosebank won’t deliver any benefits to the UK’s energy security, economy, or lower bills. It’s just more proof that this government is putting the profits of oil and gas companies over the British public and the planet.

Read more: Revealed: SNP ministers who have met with oil giant behind Rosebank

“Rosebank’s development simply cannot go ahead. And we’re taking the government to court to make sure that it doesn’t.”

Demands for a global phase-out of fossil fuels took centre stage at the COP28 UN climate summit, and the UK government’s advisers, the Climate Change Committee (CCC), recently said that the expansion of fossil fuel production is not in line with the UK’s legally-binding net zero target.

The CCC said meeting the target “means investing now in low-carbon industries to deliver lasting economic benefits to the UK” and an “unambiguous commitment to the fossil fuel phase out, accepting that global reserves are already too great.”

A UK Government spokesperson said: “We strongly reject these claims and will robustly defend any such challenge.

"The UK is a world leader in reaching net zero – cutting emissions faster than any other major economy – and as the independent Climate Change Committee recognises, we will still need oil and gas as part of our energy mix.

“We will continue to back the UK’s oil and gas industry, which underpins our energy security, supports up to 200,000 jobs, and will provide around £50 billion in tax revenue over the next 5 years – helping fund our transition to net zero.”