Rishi Sunak has suggested he would not accept a job offered by Liz Truss as prime minister, saying cabinet ministers “really need to agree with the big things”. The former chancellor said it was difficult when those at the top had fundamentally opposing views, adding: “I wouldn’t want to end up in a situation like that again.” He gave the answer to Vanessa Feltz on BBC Radio 2 as she pressed him on rumours that Truss could offer him the job of health secretary if she wins the Tory leadership as expected. “I am not focused on all of that and I doubt Liz is,” he said. “I am not thinking about jobs for me or anyone else. One thing I have reflected on as well a bit is being in a government, in cabinet, over the last couple of years, you really need to agree with the big things. Because it is tough, as I found, when you don’t. And I wouldn’t want to end up in a situation like that again.” Sunak, the underdog in the leadership contest, also gave his strongest criticism yet of Truss’s economic programme for government and accused his rival of “promising the earth to everybody”. Asked whether he had failed to be politically savvy in a contest vying for the votes of 200,000 rightwing Tory members, Sunak said: “It is being honest and, for better or worse, that is what I am going to do.” He said: “I’d love a tax cut, who doesn’t? But I think my priorities are the right ones for the country right now. Liz’s plans are promising the earth to everybody. I don’t think you can have your cake and eat it. I don’t think life is that simple, and I think her plan risks making everything worse.” His campaign earlier claimed Truss would plunge the economy into an “inflation spiral” if she does not choose between her unfunded £50bn tax cuts and providing cost of living support. Sunak’s campaign said Truss would increase borrowing to “historic and dangerous levels” and place public finances into “serious jeopardy” if she attempted to do both. An ally of Sunak’s, Kevin Hollinrake, suggested people would be homeless “on the streets” without further help to pay energy bills this winter. The MP for Thirsk and Malton told Sky News that promises by Truss’s campaign to cut taxes would provide only an extra “pound a week” to the poorest households, whereas it would provide “to the tune of about 30 a week” to a household like his. “It is simply not right,” he said. “These people are going to be on the streets. Things are going to be that bad for some households.” Sunak’s criticism of Truss has scaled up in recent days as the contest enters its final days with him appearing to trail far behind. Another Sunak supporter, Mel Stride, said Truss’s plans for an emergency budget needed to be transparent and affordable so ministers were not “flying blind”. The Commons Treasury committee chair told LBC: “At the moment the Liz camp are saying, I believe, that there will not be any OBR forecast produced at that time, and that is kind of like flying blind. “It means that you do all these dramatic things on tax etc but you don’t actually know what the independent forecaster believes the impact will be on the public finances, and I think that is quite a serious situation were that to come about.” Another Sunak supporter, Michael Gove, said in an article for the Times over the weekend that Truss was on a “holiday from reality” with her plans for tax cuts during an economic crisis. Gove, who was the levelling up secretary until being sacked by Boris Johnson before Johnson’s resignation as Tory leader, said Truss’s vision put the “stock options of FTSE 100 executives” before the country’s poorest. By contrast, the business secretary, Kwasi Kwarteng, came to Truss’s defence, saying there would be support for the poorest households regarding the cost of living crisis. Writing in the Mail on Sunday, Kwarteng said: “I understand the deep anxiety this is causing. As winter approaches, millions of families will be concerned about how they are going to make ends meet. But I want to reassure the British people that help is coming.” Truss expressed optimism for the economy, saying there was “too much talk that there’s going to be a recession”, as she insisted an economic slump was not inevitable despite the Bank of England’s forecast. In an interview with the Sun on Sunday, she said she was looking at help “across the board”, in a hint that there could be more support for businesses and households. So far she has focused on cutting taxes, such as an immediate reversal of the national insurance increase, while Sunak has focused on trying to bring down soaring inflation.