Supporters of the Tory leadership contender Penny Mordaunt are poised to target “anti-Sunak” MPs should Boris Johnson pull out of the race, amid warnings that the government will descend into “ongoing warfare” should the former chancellor win the top job. Rishi Sunak is well ahead in terms of public backers and the only one to demonstrate that he has secured the support of 100 MPs, which he needs to officially enter the race. He is likely to secure more big backers over the weekend. On Saturday he also won the support of figures previously close to Johnson – namely former Brexit minister Lord Frost and former health secretary, Steve Barclay. Sunak and his team are now working to gain the backing of as many MPs as possible to show the strength of support in the parliamentary party and send a signal to party members, in case they are asked to vote in a leadership run-off. Johnson is apparently stuck on the public backing of about 50 MPs, his team claimed that he privately now had the support of the 100 MPs required. The claim was immediately disputed. In response to reports that Johnson was well short, the Tory MP and Sunak supporter Richard Holden said: “It’s because they don’t exist.” Meanwhile, Mordaunt, the leader of the Commons, is trailing in a distant third place according to public declarations of support among MPs. Her allies say that a flurry of backers will emerge on Sunday and that a hustings on Monday will play to her strengths and change the dynamics of the race. However, allies acknowledge that her fortunes are tied to those of Johnson and that she could well force the contest to a membership vote should the former prime minister pull out. They believe there are swaths of MPs willing to back Mordaunt to stop Sunak being crowned leader without a leadership vote. “There’s a lot of people who still just hate each other – that has not changed since the summer,” said a Mordaunt ally. “It’s only intensified. That is why Penny could emerge as the genuine unity candidate. There’s Boris people who look at Rishi and just really can’t stomach him and won’t want to serve under him – and I doubt they are going to be quiet in any situation in which Rishi is prime minister. She has none of the baggage. If not first, she is everyone’s number two choice. Her private numbers are much higher than publicly listed.” The ‘anyone but Boris’ vibe is really strong among members as well as well as the public, according to another MP: “I don’t think anything is sewn up. There’s a realisation that if he won, I think a whole load of the party would just refuse en masse to obey orders.” Many MPs said that they simply did not believe Mordaunt had sufficient support and that some who wanted to back her had been put off by the experience of the Truss leadership. “There’s a ‘once bitten, twice shy’ feeling in terms of choosing a relatively unknown candidate,” said one. Mordaunt’s team are pointing to recent focus groups that they argue show she is more relatable for key sections of voters. A focus group for the More in Common thinktank suggested Sunak’s wealth came up among voters. “If you’re rich like he is, a £200 gas bill for him is an hour’s work. He couldn’t care less, but to us, it’s a weekly wage,” said one. Another said: “Rishi Sunak was good as chancellor, but that doesn’t mean he’ll be good as prime minister. The role is totally different. I think he’s a people pleaser and he was right under the wing of Boris Johnson. He turned on him, which made me wonder whether he’s truthful or reliable.” Johnson is likely to secure more support from the European Research Group of staunchly pro-Brexit MPs, who are expected to meet on Monday morning to discuss the leadership. However, it is expected that Johnson would need support beyond this cohort to secure the backing of 100 MPs.