Rishi Sunak risks damaging trust in the UK among developing countries and reducing the country’s standing in negotiations, because of a failure to meet climate spending pledges, civil servants have told ministers. They said that under current policies the only way to meet the £11.6bn international climate funding target agreed at Cop26 was to take a drastic combination of “hugely reputationally damaging” measures including delaying meeting the target, redefining already committed spending as climate funding, and cutting money for research and development, biodiversity and plastic pollution mitigation. The Guardian revealed earlier this week that Rishi Sunak was drawing up plans to drop the target. Although the Foreign, Commonwealth and Development Office (FCDO) said such claims were “false”, a leaked briefing showed that ministers were being prepared for the target not being met because of government cuts to aid funding, underspending and new commitments such as aid for Ukraine. Officials told ministers this spring that they would have to enact a “rapid but not impossible pivot towards climate-focused development” if the target was to be reached. This has not happened, and spending has remained the same. The civil servants warned: “If we do not take bold and deliberate action now, we judge that we will quickly render the £11.6bn target (and associated sub-targets) out of reach.” A document, seen by the Guardian, confirms that the government continues to underspend on its climate commitments. It states: “We have confirmed that HMG ICF [international climate fund] spend for 2022/23 was £1,347m and initial analysis of business plan returns for 2023/24 suggest that our HMG ICF spend will be c.£1,586m. This is a total of £1.1bn (£421m and £720m respectively) below the internal target trajectory agreed after the last spending review.” Civil servants have drawn up a plan for the prime minister to meet the spending commitments by 2026, none of which will be well received by countries vulnerable to climate breakdown. Currently, the proportion of bilateral development spending that would have to be climate funding would be 83% if the target was to be reached. Officials have recommended a range of options to reduce this to 50%. These include: Delay the target. Officials said they could move it to the end of the 2026 calendar year instead of the financial year 2025/26, giving another three-quarters of a year to spend money. They warned this would “be hugely reputationally damaging at a time when the global south mistrusts wealthy countries”. They added: “The geopolitical ramifications are likely to extend beyond climate, damaging our standing with a wide range of developing countries, SIDs [small island developing states], Commonwealth and middle-ground nations, further undermining trust in the UK as a donor.” Count other already-committed amounts to climate payments as part of the £11.6bn. Civil servants said: “This would be seen as the UK ‘moving the goalposts’ and would be seen as a backwards step, reducing UK standing and influence in climate negotiations.” Eat into Defra and net zero department budgets. Currently half of the international funding paid by these departments is part of the £11.6bn commitment. Civil servants said it would be helpful for this to be closer to 75%, but this would eat into research and development funding as well as non-climate biodiversity protection programmes and other areas such as preventing plastic pollution. Obtain a one-off sum from the Treasury. Officials admitted this would be “strongly resisted” by the chancellor but said if the Treasury directly funded loss and damage options, it “would be a strong signal of climate leadership by the UK”. Even a mixture of these would not necessarily get the country over the line, officials said. They told ministers: “It is possible that a combination of these measures could get us over the line – although there would remain significant risks associated with uncertainties. There is a possibility that we pull out all of the stops, take significant reputational hits in other areas and still fail to hit £11.6bn.” In the Commons on Wednesday the deputy prime minister, Oliver Dowden, said the UK was a reliable partner on climate, and that the PM remained committed to the £11.6bn pledge. He added that the aid budget was delivered by several depts, not just the FCDO, and was deliberately phased over five years. He also said that Sunak would be attending Cop28 in the UAE. Green MP Caroline Lucas said: “Not only would delaying or dropping this commitment shatter any remaining fragment of our global climate leadership; it would be just the latest in a long string of measures from this government showing total and utter disregard for some of the world’s poorest and most vulnerable, and for the accelerating climate emergency.” Environment campaigners have urged the government to make serious use of the underspend, which is forecast to add up to billions by 2026, and ringfence it separately from other aid and environment budgets. Shaun Spiers, the executive director of the Green Alliance thinktank, said: “The government’s got itself into a mess by not meeting its commitments in a timely way. They should now work up a serious plan to use this underspend to get action on nature, climate and adaptation at Cop28, using it to lever in funding from other countries, starting with the US. It could have a real impact. But it must be done transparently and not by raiding other vital development and environment budgets.” Rebecca Newsom, the head of politics at Greenpeace UK, suggested raising taxes on fossil fuel companies, whose profits each year dwarf the money committed to developing countries. “Ministers should come up with the funds needed for climate finance and loss and damage by raising taxes on fossil fuel companies – five of whom made nearly $200bn profit in 2022 alone.” The FCDO has been contacted for comment.