There is not enough evidence of policies in place that would actually reduce greenhouse gas emissions, the court said.

Energy secretary Claire Coutinho must now prepare a revised plan within 12 months. The new plan must ensure that the UK achieves its carbon budgets as well as its pledge to cut emissions by more than two-thirds by 2030.

Environmental charities Friends of the Earth and ClientEarth, along with the Good Law Project, brought a legal case against the Department for Energy Security and Net Zero (DESNZ) over its decision to approve the carbon budget delivery plan last March.

Mr Justice Sheldon has now upheld four of the five grounds of their legal challenge, saying that the decision made by former energy secretary Grant Shapps was “simply not justified by the evidence”.

He said: “If, as I have found, the secretary of state did make his decision on the assumption that each of the proposals and policies would be delivered in full, then the secretary of state’s decision was taken on the basis of a mistaken understanding of the true factual position.”

A DESNZ spokesperson said: “The UK can be hugely proud of its record on climate change. Not only are we the first major economy to reach halfway to net zero, we have also set out more detail than any other G20 country on how we will reach our ambitious carbon budgets.

“The claims in this case were largely about process and the judgment contains no criticism of the detailed plans we have in place. We do not believe a court case about process represents the best way of driving progress towards our shared goal of reaching net zero.”

Stephanie Lowe, deputy chief executive of the Scottish and Northern Ireland Plumbing Employers’ Federation (SNIPEF), has called for the urgent development of a more robust, fair, and actionable climate strategy.

“The High Court’s ruling, which requires the government to revisit its climate action plan, underscores the urgent need for realistic and achievable climate goals,” said Lowe. “This decision aligns with our longstanding call for government strategies that are ambitious yet grounded in the practical realities and expert insights from industries at the forefront of implementing these technologies.”

Ms Lowe added: “Incorporating detailed, industry-informed pathways is crucial to ensure the targets set are not merely aspirational but truly achievable. It is essential that future climate policies adopt a balanced approach that includes all sectors and communities.”

The ruling highlights the challenges in current government plans, which have been criticised for their lack of detail on achieving proposed emission cuts. As noted by environmental groups and the recent judicial review, the plans require a more comprehensive framework that genuinely aligns with the UK’s net-zero ambitions.

“We urge the government to use this opportunity to engage more constructively with industry experts and stakeholders to craft a plan that is both comprehensive and feasible,” Ms Lowe stated. “SNIPEF is committed to supporting a transition to low-carbon technologies and looks forward to participating in a dialogue that moves us closer to our shared environmental goals.”