Jeremy Hunt has insisted that Liz Truss is in charge despite her premiership looking increasingly in peril, as he warned of further public spending cuts and failed to rule out more U-turns on her disastrous mini-budget. The new chancellor, now widely seen as the most powerful man in government since he took over from the sacked Kwasi Kwarteng, has buried a series of flagship policies that brought Truss to power. “The prime minister is in charge,” he told the BBC’s Sunday with Laura Kuenssberg, even though her authority has been seriously undermined by her decision to allow him to tear up her economic agenda in an attempt to calm the markets and mutinous Tory MPs. Hunt claimed the prime minister had changed, as he defended her credibility as leader. Asked why people should trust what she or the government said, he replied: “Because she’s listened. She’s changed. She’s been willing to do that most difficult thing in politics, which is to change tack. What we’re going to do is to show not just what we want, but how we’re going to get there.” However, the former health secretary appeared to rule out any future tilt at the Tory leadership, saying his desire to lead the party had been “clinically excised” thanks to previous failed attempts. “I think having run two leadership campaigns, and by the way failed in both of them, the desire to be leader has been clinically excised from me,” he said. “I want to be a good chancellor. It’s going to be very, very difficult. But that’s what I’m focusing on.” Hunt and Truss met in her Chequers residence on Sunday with tax rises and spending cuts on the horizon, and the new chancellor admitting that “difficult decisions” are coming over the next two weeks, before the new budget on 31 October. “Actions speak louder than words,” he said, as he promised to reassure the markets. Truss has already been forced into a humiliating climbdown on her plans for a top 45p rate tax cut and a freeze in corporation tax, which will now go from 19% to 25%. The chancellor is also expected to delay Truss’s promised 1p cut to the basic rate of income tax by a year, as he struggles to fill a multibillion-pound fiscal black hole in the economy. “I’m not taking anything off the table,” he said. “I want to keep as many of those tax cuts as I possibly can because our long-term health depends on being a low-tax economy. And I very strongly believe that.” The chancellor warned that no government department would be immune from “efficiency savings”, as he signalled spending cuts to come, including on defence and health, despite warnings the NHS is already on its knees before a difficult winter. “I’m going to be asking every government department to find further efficiency savings,” he said. However, he dropped a hint that benefits could be uprated in line with inflation, rather than earnings, in April, by claiming his would be a “compassionate Conservative government” and that those on the breadline would be “top of our minds” in the weeks ahead. Hunt said the public now wanted an “honest chancellor” but denied he was implying his predecessor had not been. The senior Tory backbencher Robert Halfon, meanwhile, did not deny that some of his colleagues were plotting how to remove Truss. “Of course, colleagues are unhappy with what is going on,” he told Sky News. “We’ve haemorrhaged in the opinion polls. The public just can’t understand what has happened. Many of them are frightened about their future and the cost of living. It’s inevitable that colleagues are just, we’re all talking to see what can be done about it.” Halfon added that over the last few weeks the government had “looked like libertarian jihadists” and treated the country like “laboratory mice” for economic experiments. “This is not where the country is. There has been one horror story after another. It’s not just about tax cuts for the rich. It’s also about about benefit cuts.” The Tory MP Crispin Blunt was the first to stick his head above the parapet, saying he did not think the prime minister could survive the current crisis. “I think the game is up and it’s now a question as to how the succession is managed,” he said. The former minister, who was the first MP to call for Iain Duncan Smith to quit as party leader in May 2003, added: “If there is such a weight of opinion in the parliamentary party that we have to have a change, then it will be effected. Exactly how it is done and exactly under what mechanism ... but it will happen.” Truss’s plans also faced international criticism with the US president, Joe Biden, calling Truss’s abandoned UK tax cut a “mistake” and saying he was worried other countries’ fiscal policies may hurt the US amid “worldwide inflation”. Biden said it was “predictable” that the new British prime minister was forced on Friday to walk back plans to aggressively cut taxes without identifying cost savings, after her proposal caused turmoil in global financial markets. It marked an unusual criticism by a US president of the domestic policy decisions of one of its closest allies. “I wasn’t the only one that thought it was a mistake,” Biden said. “I think that the idea of cutting taxes on the super-wealthy at a time when … I disagree with the policy, but that’s up to Great Britain.”