A historic legal judgement has ‘fundamentally changed’ the landscape around planning permission for fossil fuel extraction, campaigners have said.

The Supreme Court ruled today that Surrey County Council acted unlawfully when it granted permission for oil drilling at Horse Hill, near Horley, without considering the climate impacts of the inevitable burning of the oil.

Surrey’s environment impact assessment failed to consider the fact that more than 10m tonnes of carbon emissions would be produced when the extracted oil was burned.

While such ‘downstream’ emissions are increasingly omitted when planning authorities consider fossil fuel projects, the Supreme Court has now recognised that the damaging impact of emissions is not limited to where fossil fuels originate, according to law firm Leigh Day.

Sarah Finch, who challenged Surrey’s decision on behalf of the Weald Action Group, said: ‘The oil and gas companies may act like business-as-usual is still an option, but it will be very hard for planning authorities to permit new fossil fuel developments when their true climate impact is clear for all to see.’

The Weald Action Group said the ‘groundbreaking’ judgement could have ‘profound implications’ for planning decisions on new fossil fuel projects.

A host of previous decisions could also be impacted by the ruling, such as the permission granted for a new coal mine in Cumbria and development of the Rosebank oil field in the North Sea, according to Friends of the Earth.

A Surrey County Council spokesperson said: ‘Council officers at the time of the planning application assessment believed that they acted in compliance with the law.’

The local authority, which approved oil drilling at Horse Hill just months after declaring a climate emergency in 2019, said planning permission for the scheme would be determined ‘in due course’.