Michael Gove has launched a sustained broadside at Liz Truss’s economic plans, saying it was “not Conservative” to fund tax cuts from borrowing and marked a betrayal of the party’s one nation 2019 election manifesto. In a frantic day of interventions, the former levelling up secretary first told BBC One – while Truss watched from the same studio – that it was probable he could not back the tax cuts in parliament, before embarking on a string of similarly damning fringe appearances at the Conservative conference. While Gove insisted he was not in contact with other Conservative MPs, his status in the party is likely to make him a focus for a growing backbench rebellion over Truss’s decision to scrap the top rate of tax and the cap on bankers’ bonuses. Despite warnings from the Conservative party chair, Jake Berry, that MPs who voted against the fiscal measures would lose the Tory whip, so far 12 backbenchers have said they plan to do this. The mooted idea that the government would trim the welfare budget to pay for such changes was inconceivable, Gove said, telling the prime minister in effect that she had to change course or risk her mini-budget being voted down. “It’s going to be very, very, very difficult to argue that it is right to reduce welfare, when we’re also reducing taxes for the wealthiest,” Gove told one fringe event in Birmingham, organised by the Daily Telegraph. The 2019 manifesto was “a one nation majority” that must be respected, Gove said: “People wanted Brexit done but they also wanted levelling up. They wanted a Conservative government that was dedicated to improving the lives of those who hadn’t necessarily been traditional Conservative voters, and certainly were not among the wealthiest in society. And we’ve got to stay true to that tradition.” In an early morning appearance on BBC One’s Sunday with Laura Kuenssberg show, directly after Truss had been interviewed, Gove said he backed moves to limit energy bills, but the fact that 35% of additional borrowing in the fiscal statement went on unfunded tax cuts left him “profoundly” concerned. “There are two major things that are problematic with the fiscal event,” he said. “The first is the sheer risk of using borrowed money to fund tax cuts. That is not Conservative. The second thing is the decision to cut the 45p rate, and indeed at the same time to change the law on how bankers are paid in the City of London. “Ultimately, at a time when people are suffering … when you have additional billions of pounds in play, to have a principal decision, the headline tax move, cutting tax for the wealthiest, that is a display of the wrong values.” Pressed earlier on whether he would vote against the package in the Commons, Gove eventually told Kuenssberg: “I don’t believe it’s right.” At the Telegraph event, Gove again hinted he would vote against the tax package as it stood, and urged Truss to change course. He said: “I think it would be wise of us to recognise that they are neither the right economic nor the right political response to the situation we face at the moment. If a mistake has been made then I think the right thing to do is to acknowledge that, and to correct course.” With both the chancellor, Kwasi Kwarteng, and Truss saying they are not about to reverse the policy, Gove said he was “going to have a conversation within the party and the country” about what to do next. At a later fringe event, hosted by the Onward thinktank, Gove said it was “not in the best Conservative traditions” to fund such large-scale tax cuts with borrowing. He said: “Millionaires will gain by tens of thousands of pounds as a result of these tax cuts – and people on average and below-average incomes will not, and that I think is the wrong priority.” However, he said her gamble could work, joking: “If I’m proven wrong, then Liz will not only have grown the pie, she will also have ensured that there is a massive humble pie that I will have to eat.”