Britain’s highest court has ruled that local councils and planning groups must consider the full environmental impact of new fossil fuel projects when deciding whether to approve them, a decision that could have far-reaching consequences and that climate activists hailed as a major victory.

In particular, the ruling will make it harder for Britain to move ahead with plans to develop large offshore oil fields in the North Sea, including Rosebank, one of the country’s largest undeveloped oil fields. Situated off the coast of Scotland, Rosebank contains an estimated 300 million barrels of recoverable oil.