The battle to become the UK’s next prime minister descended into fierce clashes on Monday night as Rishi Sunak launched repeated attacks on the economic policies of the favourite Liz Truss in their first head-to-head TV debate. The two Conservative leadership hopefuls traded blows over tax cuts, China and inflation, with the former chancellor Sunak accusing the foreign secretary of seeking “a short-term sugar rush” by cutting national insurance. Truss accused her former cabinet colleague of raising taxes to their highest level for 70 years. The exchanges at the BBC debate followed a weekend of deeply personal attacks – with Sunak criticised over his wealth and wardrobe, as Truss faced claims she was economically illiterate while being reminded that she was formerly a remainer. Sunak, widely seen as having to make up crucial ground to win over the Conservative membership, who will vote from 5 August, repeatedly described his opponent’s plans on the economy as “not conservative”, interrupting her at one point to say: “You promised almost £40bn of unfunded tax cuts, £40bn more borrowing. “That is the country’s credit card. It’s our children and grandchildren … everyone here … who are going to have to pick up the tab for that.” Truss hit back over Sunak’s calls for a tougher stance on China, pointing out that the Treasury just last month was calling for closer bilateral and economic ties. Sunak accused his opponent of making pronouncements about a “golden era” between China and the UK. “I think that was almost a decade ago,” the foreign secretary snapped back. Amid reports that Boris Johnson has not yet ruled out a political comeback, despite pledging to step down next month, both candidates also ruled out a role for the current PM in any government they might lead. “I am sure he will have a role. I am sure he will be vocal, but he will not be part of the government,” said the foreign secretary, despite emphasising that she had been an early supporter of Johnson’s. She contrasted her continuing loyalty to him to those of others, adding that “it would have been a dereliction of duty” not to remain in her post. Advertisement According to the Daily Telegraph, Johnson told Lord Cruddas at Chequers over lunch on Friday that he “wants to fight the next general election as leader of the Conservative party”, the peer said. Cruddas is running a campaign to give Conservative party members a vote on whether to accept Johnson’s resignation as Tory leader. But Downing Street responded by insisting Johnson will leave the post when a new leader is chosen. On Johnson, Truss told the debate: “Having spent time with him this week on foreign affairs, I very very much suspect he would not want a future role in the government. He needs a well-earned break.” Sunak, whose resignation from cabinet on the same day as Sajid Javid precipitated the ousting of Johnson, paid tribute to Johnson as “remarkable” but said he had reached a point where “enough was enough”. “I thought all the things that were going on on the conduct side were not right … and we clearly had different views on the economy side,” he said. But with postal ballots set to arrive on Tory members’ doorsteps by 5 August, Sunak faced pressure to use the BBC debate – and another hosted by TalkTV and the Sun on Tuesday – to make an early breakthrough. Although he comfortably won the leadership race among Tory MPs, Truss is the favourite to win after a series of opinion polls and surveys put her firmly ahead with party members. Perhaps as a result of this pressure on Sunak, the debate was particularly bad-tempered, with the former chancellor often interrupting Truss. At one point, she said: “Under my plans, we would start paying back the debt in three years’ time, so I’m not putting it on the never never.” The former chancellor interrupted, saying, “That’s simply not right”, adding: “You promised almost £40bn of unfunded tax cuts … that is the country’s credit card.” Truss said: “Rishi, that is not true. Under my plans, we would start paying down the debts in three years’ time. Covid was a one-in-100-years event. No other country is putting up taxes at this moment. The OECD has described Rishi’s policies as contractionary.” In the aftermath of the debate, supporters of Truss argued that Sunak’s interruptions were a result of his entitled background. “He came across like a public school mansplainer,” said one. One Sunak supporter claimed that Truss did not understand the economy. “She was once again out of her depth,” the MP said. Advertisement Party grandees spoke out in the hours before the debate, pleading for both parties to resist from “trashing the brand”. But the tensions that have been building continued to manifest themselves, with Truss declining to distance herself from comments by a supporter, the culture secretary, Nadine Dorries, who outraged some fellow Tory MPs by comparing Sunak’s Savile Row suit and Prada shoes to Truss’s £4.50 earrings from Claire’s Accessories. “I am not going to give Rishi fashion advice. I mean, I have said he is a very well-dressed man. I’m not going to give him fashion advice,” said Truss, when challenged about Dorries’ comments. Lord Maude, the former party chair and minister for the Cabinet Office, had told the BBC’s PM programme ahead of the debate: “One is obviously going to win the leadership, but if the behaviour of the teams and their language has been uncontrolled, and it has damaged the party’s standing or the way people see the party, then it could end up being a pyrrhic victory.” He said that the increasingly fractious tone of interventions from the campaign teams over the weekend had begun to appear like “a race over who can sound more rightwing, as if that’s the only game in town”. Allies of Sunak said it was “no secret” that he had to make a significant impression in the debate, with polls suggesting he is trailing his rival. But one campaign source said the polling from both YouGov and ConservativeHome showed a wider gulf between the candidates than they had detected and said many members were undecided. Truss has strictly limited her broadcast appearances and has thus far declined to be interviewed by veteran political journalist Andrew Neil, who will go head-to-head with Sunak on Friday. Channel 4 said it was still hoping to convince Truss to take part. Allies of Sunak have suggested he will take numerous broadcast opportunities in order to highlight one of his own strengths versus Truss’s perceived weakness. In previous multi-candidate debates, Truss has polled badly with the general public, whereas Sunak came top in one debate and second in another. Earlier on Monday, Sunak teased his rival with a tweet – “Just me then?” – and a wink as Channel 4 announced the interview with Neil. Truss’s refusal echoes that of Boris Johnson, who refused to be interviewed by Neil during the 2019 general election campaign. Sunak and Truss will take part in another head-to-head debate on TalkTV on Tuesday night, and face off again at the first of the members’ hustings in Leeds on Thursday night. Truss is likely to come under scrutiny when she returns to her home city on Thursday after multiple speeches criticising her former comprehensive school in north Leeds, which she said spent “too little time spent making sure everyone could read and write … there was a preference for symbolic gestures”. The remarks have been criticised by the former Conservative MP for the area and by city councillors.