The UK government’s climate action plan is unlawful, the high court has ruled, as there is not enough evidence that there are sufficient policies in place to reduce greenhouse gas emissions. The energy secretary, Claire Coutinho, will now be expected to draw up a revised plan within 12 months. This must ensure that the UK achieves its legally binding carbon budgets and its pledge to cut emissions by more than two-thirds by 2030, both of which the government is off track to meet. The environmental charities Friends of the Earth and ClientEarth took joint legal action with the Good Law Project against the Department for Energy Security and Net Zero (DESNZ) over its decision to approve the carbon budget delivery plan (CBDP) in March 2023. In a ruling on Friday, Mr Justice Sheldon upheld four of the five grounds of the groups’ legal challenge, stating that the decision by the former energy security and net zero 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.” The judge agreed with ClientEarth and Friends of the Earth that the secretary of state was given “incomplete” information about the likelihood that proposed policies would achieve their intended emissions cuts. This breached section 13 of the Climate Change Act, which requires the secretary of state to adopt plans and proposals that they consider will enable upcoming carbon budgets to be delivered. Sheldon also agreed with the environment groups that the central assumption that all the department’s policies would achieve 100% of their intended emissions cuts was wrong. The judge said the secretary of state had acted irrationally, and on the basis of an incorrect understanding of the facts. This comes after the Guardian revealed the government would be allowing oil and gas drilling under offshore wind turbines, a decision criticised by climate experts as “deeply irresponsible”. The CBDP outlines how the UK will achieve targets set out in the sixth carbon budget, which runs until 2037, as part of wider efforts to reach net zero by 2050. Those emissions targets were set after a 2022 ruling that Britain had breached legislation designed to help reach the 2015 Paris agreement goal of containing temperatures within 1.5C (2.7F) of pre-industrial levels. The Climate Change Committee’s assessment last year was that the government only had credible policies in place for less than 20% of the emissions cuts needed to meet the sixth carbon budget. The lawyer for Friends of the Earth, Katie de Kauwe, said: “This is another embarrassing defeat for the government and its reckless and inadequate climate plans. We’ve all been badly let down by a government that’s failed, not once but twice, to deliver a climate plan that ensures both our legally binding national targets and our international commitment to cut emissions by more than two-thirds by 2030 are met. “We urgently need a credible and lawful new action plan that puts our climate goals back on track and ensures we all benefit from a fair transition to a sustainable future. Meeting our domestic and international carbon reduction targets must be a top priority for whichever party wins the next general election.” Ed Miliband, the shadow energy secretary, said: “This is a new low even for this clown show of a government that has totally failed on energy and climate for 14 years. Their plan has now been found unlawful twice – once might have been dismissed as carelessness, twice shows they are incapable of delivering for this country. “The British people are paying the price for their failure in higher bills, exposed to the dictators like [Vladimir] Putin who control fossil fuel markets. Only Labour can tackle the climate crisis in a way that cuts bills for families, makes Britain energy independent, and tackles the climate crisis.” Caroline Lucas, the Green party MP, said: “Once again the government’s climate plan has been ruled unlawful. When dealing with the climate emergency, simply ‘hoping for the best’ and putting your faith in unproven technologies and vague policies is not good enough – we need concrete plans and investments and there is no time to lose. The government must now go back to the drawing board and urgently pull together a credible plan to put the UK back on track to delivering our climate commitments.” John Barrett, professor in energy and climate policy at the University of Leeds, said: “The UK government has failed to describe a credible pathway for the UK to achieve its legally binding climate commitments. This is despite overwhelming evidence from the Climate Change Committee and university researchers on the various options available to the government. Many of these options also deliver numerous co-benefits such as warmer homes, cheaper bills, more energy security, better air quality, more jobs and a healthier society. It is time for the UK government to take climate change seriously and tell us how they are going to achieve their own targets.” 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.”