Mordaunt’s campaign claimed Foreign Secretary Liz Truss could not win the general election and that if she became prime minister Tory MPs risked losing their seats. Former chancellor Rishi Sunak is widely expected to be shortlisted when the result of the fifth round of voting is announced by Tory MPs at 4pm on Wednesday. Sunak won 118 votes on Tuesday, just two short of the 120 needed to be sure of a runoff, but there is a tight race for second place on the final ballot. Mordaunt secured 92 votes on Tuesday, just six ahead of Truss on 86. Truss believes she has momentum and can overtake her rival in the final round of voting. After Wednesday’s vote, around 150,000 Conservative campaigners will vote on which of the two candidates they want to be their party leader and prime minister, with the result to be announced on September 5. In a statement from Mordaunt’s camp, a campaign official said the trade secretary represented “change” – unlike Sunak and Truss who did not serve in Boris Johnson’s cabinet – and a “fresh start”. Mordaunt claimed to be running a clean campaign, but as the final vote approached, the gloves came off. “Liz Truss will not be able to win the general election and she would put MP seats at risk,” said a Mordant aide. Mordaunt herself retweeted a Daily Telegraph column by Allison Pearson with the headline: “Vote for Rishi Sunak or Liz Truss today and you’ll kill the party you love.” Mordaunt later deleted the tweet. A Truss campaign spokesman said: “Party murder? Seriously? Liz has a bold financial plan to tackle the cost of living — and more experience, credibility and weight on this main topic of the day.” Mordaunt’s bid to fight Truss received a boost when she received the support of Damian Green, head of the moderate One Nation group of Conservative MPs. Green, de facto deputy prime minister under Theresa May, said he had thought long and hard before backing Mordant. “It offers a fresh start and an opportunity to unify the party and deliver for the country,” he said.

Much depends on how the 59 supporters of Kemi Badenoch, who was eliminated from the contest on Tuesday, split in the final round of voting. Truss hopes many will back her and has called on the Tory right to “rally” behind her candidacy. Some Conservative MPs have suggested that Sunak, who appears certain to make it to a head-to-head contest, could “lend” supporters to the candidate he would most like to face in the final stage of the contest. However, polls show both Mordaunt and Truss are currently more popular with members than Sunak, and it is unclear which candidate would pose a greater threat to the former chancellor. Mordaunt would offer a clean break from the Johnson era, but is seen by Sunak’s team as light on experience and sloppy on finances. Meanwhile, Mr Sunack’s supporters argue that Truss is too divisive a figure for the general public to convince Tory members that he could lead the party to a fifth successive general election victory.