Climate campaigners celebrate outside the Court of Session in Edinburgh following a ruling overturning the approval of Equinor's Rosebank oil development in the North Sea. Image: Stop Rosebank

Greenpeace his raised concern that the Government has already decided to grant approvals to the Rosebank oilfield after courts deemed the UK government’s approval of the project was unlawful.

The climate campaigning group, alongside fellow activists Uplift, took the UK government to court late last year over the approval of Shell’s Jackdaw and Equinor’s Rosebank oilfields.

The landmark ruling went in favour of Greenpeace and Uplift and has forced the UK government to rethink how it assesses the environmental impact of North Sea oil production, particularly in relation to downstream – also known as scope three – emissions.

However, Greenpeace has raised concerns that the Labour Government has already decided to approve the Rosebank EIA without following “due process”.

Mel Evans, climate team leader at Greenpeace UK, said: “These noises coming from the government are concerning.

“If a political decision to approve Rosebank and Jackdaw has already been made behind closed doors without following due process, we won’t hesitate to take legal action.”

Rachel Reeves, Chancellor of the Exchequer presenting the Autumn Budget.

Greenpeace lawyers have sent a letter to energy secretary Ed Miliband and the North Sea Transition Authority (NSTA) after comments made by chancellor Rachel Reeves and prime minister Keir Starmer that the group believes indicated that a decision has already been made on the future of the UK’s largest untapped oilfield.

In a recent interview with The Sun newspaper, Reeves said: “We said in our manifesto that they would go ahead, that we would honour existing licenses, and we’re committed to doing that, and go ahead they will.

“North Sea oil and gas is going to be really important to the UK economy for many, many decades to come. And we want to make sure that fields that have already got licenses can continue to exploit those reserves and bring them to market.”

This has served as the “clearest indication yet that the government may have already made the decision to approve Rosebank and Jackdaw,” Greenpeace said.

Evans added: “Rosebank is a vast field with enough oil and gas to cause as much carbon pollution as 56 coal plants running for a year.

“There is no way that it could be approved after the full emissions are taken into account. Any serious environmental impact assessment would show that it is completely incompatible with our climate commitments.

“The government did the right thing by sticking to their pledge to ban new oil and gas licences, but now they must fully comply with the court ruling on Rosebank and Jackdaw.”

Rosebank balmoral — The Knarr FPSO, which will be used for production on the Rosebank project in the West of Shetland.

Equinor has said that it aims to electrify operations at the Rosebank project, however, electrification will arrive in 2030 at the “earliest”.

The Norwegian state-owned oil firm previously argued that, with Rosebank electrified, it will have emissions of 3 kg of CO2 per barrel, “one of the lowest ever CO2 footprints” in UK waters, compared to a sector average of 20 kg per barrel.

“More drilling for fossil fuels in the North Sea is an economic dead end – it won’t bring down energy bills or guarantee the economic growth Reeves is looking for,” Evans continued.

“While the UK oil and gas industry has been losing jobs despite new licences being issued, UK business leaders say the green sector is growing three times faster than the rest of the economy and employing almost a million people in full-time jobs.

“Reeves and Starmer must turn their attention to the huge opportunities that green growth presents.”