The toxic briefings between Tory leadership teams intensified as the two candidates traded blows over the economy, immigration and UK national security ahead of the first head-to-head TV debate.
Rishi Sunak’s camp has accused Liz Truss of changing her stance on China’s influence in the UK education system, claiming she was responsible for opening a third of the UK’s Confucius Institutes, when she was an education minister.
China hawks on the Tory backbenches are deeply concerned about the presence of the Chinese institutions in schools and universities, believing they are a propaganda arm for Beijing.
Mr Sunak’s supporters told i that the Foreign Secretary has only since changed her mind on China’s threat, likening it to her change from “being a Lib Dem, Remainer and a Cameroon”.
The Truss campaign immediately hit back, claiming Mr Sunak was “too soft” on China, adding that the Chinese state media was “effectively endorsing Rishi Sunak for Prime Minister”, highlighting a recent China Daily Post article that praised Mr Sunak’s “pragmatic approach” to UK-China relations.
The comments show the battle to replace Boris Johnson is turning ever nastier and sets up what is likely to be a bruising encounter between the two in the first one on one TV debates on the BBC on Monday night.
The two camps spent the weekend launching bitter attacks against one another, with the latest skirmish over their respective immigration policies that saw the Truss camp branding her counterpart’s plans as not “grounded in reality” and “unworkable”.
On the issue of using cruise ships to house migrants, rather than hotels the Team Truss said it would be illegal under the Human Rights Act.
It prompted allies of the Sunak camp to claim the attacks were because their rival’s immigration plans had “no substance” dismissing them as “lightweight”, adding it was “good to see Remainer Truss on the side of human rights lawyers”.
Mr Sunak was equally scathing of his opponent’s economic plans on Saturday, when he described her proposals to make £30bn worth of tax cuts as “immoral”.
The former chancellor is desperately trying to fight his way back into contention in the race for Downing St after several sets of polls showed him to be behind his counterpart.
Despite his attempts to denounce Ms Truss’s economic proposals, they remain popular among Tory members and she still holds a commanding lead according to recent polls.
Mr Sunak’s campaign team said he was willing to take on his counterpart in any policy area as he seeks to gain ground on his rival.
The bitter briefing war comes despite desperate pleas from fellow Conservatives over the weekend for a clean fight between the two.
Asked whether the candidates will limit their attacks on one another, a Tory backbencher told i: “I really hope so. We can’t just have a summer where the two of them are kicking lumps out of each other.”
One Tory MP said they hoped the candidates would tone down the attacks in the debate, urging them to give some thought to once the race is over. “They should be very mindful of how they conduct themselves in the contest,” the source said.