Rishi Sunak has accused his rival Tory leadership candidates of promoting ‘socialism’ by promising unfunded tax cuts, as the party’s deep divisions over economic policy were exposed in a moody TV debate .

As the suitors repeatedly clashed over tax and spending in the debate on ITV, Liz Truss confronted her former cabinet colleague, saying: ‘Rishi, you have raised taxes to the highest level in 70 years. It will not stimulate economic growth.

“The fact is that raising taxes right now will stifle economic growth,” she added.

Truss has promised tax cuts worth up to £30billion, suggesting they can be funded by more borrowing and faster growth.

Sunak insisted there would be a cost to the immediate tax cuts, however, in “higher inflation, higher mortgage rates, eroded savings.”

“And you know what, this something-for-nothing economy isn’t conservative, it’s socialism,” he said. “If we’re not for sound money, what good is the Conservative party?”

The hard-fought leadership race, sparked by the reluctant resignation of Boris Johnson as Tory leader 10 days ago, has pitted his current and former cabinet colleagues against each other.

Truss, who has the backing of Johnson loyalists including Jacob Rees-Mogg and Nadine Dorries, notably defined herself against Sunak, who led the first two rounds of voting among MPs.

He has, however, strongly defended his record as Chancellor – including the decision to increase National Insurance contributions.

As well as questioning her colleagues’ tax cut plans, Sunak also accepted Penny Mordaunt’s suggestion earlier on Sunday that she could drop one of her budget rules – the promise to borrow only for invest, not for day-to-day expenses – to allow the treasury to spend more to meet the cost of living.

Asked about it, Mordaunt said: “Too many chancellors have had too many budget rules which they then had to abandon because they were unable to stick to them,” prompting Sunak to hit back: “Literally, Jeremy Corbyn didn’t think that was the right approach.

Taxes and the economy were at the heart of the contest, with Sunak the only contestant not to promise immediate tax cuts, instead promising not to tell “fairy tales” about what is affordable.

With each candidate given the opportunity to interview one of his colleagues, three of Sunak’s four rivals turned against him.

Kemi Badenoch asked him why he hadn’t taken more action against Covid loan fraud, despite her and other ministers raising the issue with him during the pandemic.

He said, “That’s absolutely not right,” pointing to how quickly the device had to be deployed. Truss asked Sunak if he was still in favor of investing in China, and Mordaunt wondered if he had done enough as chancellor to fund defense spending.

Sunak turned on Truss, asking him, “You were both a Liberal Democrat and a Remainer: I just wonder which of those you missed the most?” The Foreign Secretary said she was not born into a Conservative household and had been on a political ‘journey’.

She also returned to the familiar theme at her comprehensive school in Leeds, where she says other pupils were let down by low expectations, which contributed to her shift to the right.

Shortly before the debate, Sunak’s team released an original Pathé News-style black-and-white video drawing attention to the fact that he had backed Brexit in 2016, while Truss had not.

Conor McGinn, Labour’s deputy national campaign co-ordinator, said the style of it “seems about right for the guy who, as chancellor, brought us the highest taxes and the biggest drop in the standard of living in 70 years…Rishi Sunak took us back to the 1950s.”

One of the few defining moments of consensus in the debate, in which the candidates clashed repeatedly, was when presenter Julie Etchingham asked them to raise their hands if they wanted to welcome Boris Johnson into their cabinet.

None of them did – although Mordaunt said ‘he got Brexit done’. All five also said they would not call a general election to give them a mandate if they win the leadership contest this fall.

Tom Tugendhat attacked his rivals for staying in government to support Johnson, saying: “Even very good people gave credibility to the chaos.”

Dominic Raab, the deputy prime minister, who backs Sunak, earlier suggested that Truss’s record in government belied his claim to cut taxes. “Liz can answer for her policies and her record; she was Chief Secretary to the Treasury. People can see if public service spending and headcount has gone up or down,” he told Sophy Ridge on Sky News. “Did she cut taxes at that time?”

The debate was the second of three televised matchups between the candidates. Half of the initial field of 10 contenders, including Sajid Javid and Jeremy Hunt, have already been eliminated, after two rounds of voting.

Further votes among MPs will take place on Monday, Tuesday and if necessary Wednesday, with the final two candidates then presented to Conservative MPs, who will make the final decision by September 5.

A new online survey of party members, published Sunday by the Conservative Home website, suggested that Mordaunt’s popularity may have peaked. It showed Truss beating Sunak by 49% to 42% and Mordaunt by 48% to 41% in direct comparisons.

Mordaunt had previously criticized what she called the race’s “toxic politics” and “libeled” it against her.

Leaked documents at the Sunday Times suggested that Mordaunt was prepared to drop some, but not all, of the medical requirements for people choosing to change gender.

Badenoch, his successor as equality minister who is also running for leadership, said Mordaunt’s position in the past has been to push for self-identification. This contradicts Mordaunt’s insistence during Friday’s Channel 4 debate that she was ‘never in favor of self-identification’.

Badenoch told The Sunday Times: “I’m not going to call her a liar, I think it’s very possible that she really didn’t understand what she was signing. It’s a very complex area.