Andy Burnham has been urged to “stick to the spirit of Labour’s manifesto commitment” and refuse consent for the controversial Jackdaw and Rosebank oil and gas fields.

Stop Climate Chaos Scotland (SCCS) – a campaign group made up of more than 70 different organisations with around one million supporters – insisted the new Prime Minister must block the proposed new developments in the North Sea.

It told the Prime Minister that the lifetime carbon emissions from the two proposed developments could result in up to 65,495 excess heat deaths by the end of this century – adding this would be equivalent to the entire population of the city of Inverness.

A letter to Mr Burnham told how analysts have already linked  the heatwaves in May and June this year to more than 2,700 excess deaths in England and Wales.

SCCS added that Scotland also experienced a “devastating wildfire” in the Cairngorms National Park this summer which “required a major and sustained emergency response”

The plea comes ahead of the public consultation on Rosebank – the largest untapped oil field in the North Sea which lies some 80 miles north west of Shetland – closing on Monday.

A similar exercise for the planned Jackdaw gas field, which lies in waters about 150 miles east of Aberdeen, finished on August 10.

Production at both fields had been approved by the previous Conservative government, but those decisions were quashed after a legal challenge from Greenpeace, leaving Labour ministers to decide now whether or not drilling should go ahead.

It comes as the Met Office said it is “increasingly likely” that 2026 will the UK’s hottest ever summer, leaving all of Wales and much of England facing drought conditions.

In a letter seen by the Press Association and sent to both the Prime Minister and Energy Secretary Miatta Fahnbulleh, SCCS warned that the “consequences of climate change are already being felt, through more extreme heat, drought, wildfires and growing risks to food insecurity”.

They were told that approving Jackdaw and Rosebank would have “consequences for the UK’s international climate leadership”.

While the campaigners said the UK had “made progress in reducing emissions”, they warned that “credibility will be undermined” if new developments in the North Sea are given the go ahead.

“It becomes much harder for the UK to ask others to move away from fossil fuels if it continues approving major new fields at home,” the letter added.

Signed by groups including Friends of the Earth Scotland, the Environmental Rights Centre Scotland and Fuel Poverty Action, it insisted: “Approving Rosebank and Jackdaw does not lower energy bills for UK households, nor does it future-proof employment in the energy sector.

“By contrast, investing in clean, home-grown renewable energy can strengthen energy security while creating secure, long-term jobs that benefit individuals and communities and are not dependent on the volatility of global fossil fuel markets.”

The letter claimed that approving new fields such as  Rosebank and Jackdaw is “not compatible with climate goals”.

It continued: “Oxfam estimates that Rosebank and Jackdaw’s combined lifetime carbon emissions could cause up to 65,495 excess heat deaths by 2100, a toll equivalent to the entire population of Inverness.”

SCCS urged the PM to reject both Jackdaw and Rosebank and “make this a decisive moment to accelerate investment in home energy efficiency, renewables and clean energy manufacturing”.

A spokesperson for the Department of Energy Security and Net Zero said: “The North Sea remains a vital national asset, supporting jobs, growth and the UK’s energy security.

“We are clear that oil and gas will continue to play an important role in our energy system for decades to come, alongside transitioning to clean power to protect jobs and tackle the climate crisis.”