As the Conservative leadership candidates are whittled down to a final two, it’s becoming a case of “anyone but”. Already three of the 11 candidates have had to drop out owing to insufficient support: the transport secretary, Grant Shapps, the former health secretary, Sajid Javid, and the lesser known Rehman Chishti all failed to secure the 20 MP nominations required to make the ballot. With eight candidates remaining, two main camps are forming: “Stop Rishi” and “Stop Liz”. The first group is unnerved by Sunak’s fast ascent as the favourite in the leadership race. While Sunak spent much of his early time in No 11 as the golden boy and bookies’ favourite to succeed Johnson, many of his critics had written off his chances after his popularity plummeted following a row over his wife’s non-dom tax status and his possession of a green card. The fact that he has picked up the most MP nominations has thereby caught them off guard. “It’s anyone but Rishi for me,” says a member of the 2019 intake. Sunak’s critics fall into two teams, roughly: MPs such as Jacob Rees-Mogg, who believe he betrayed Boris Johnson and played a key part in his downfall; and MPs on the right of the party, who take issue with his refusal to opt for tax cuts now. Meanwhile, Johnson’s most dedicated supporters are more than happy to give interviews on Sunak’s alleged bad behaviour. The Sunak camp is trying to bat this off by bringing in supporters to the campaign who are also viewed as loyal to Johnson. It’s no coincidence that the deputy prime minister, Dominic Raab, was picked to introduce Sunak onstage at his launch. The latest endorsement by Steve Barclay – who was drafted in as Johnson’s chief of staff earlier this year when he was in a vulnerable situation – is also intended to help fix this. Yet no one wants to be a frontrunner in a Tory leadership contest as it means you have a target on your back. There is concern among some of Sunak’s backers that he could run out of steam. Can he really go through an entire leadership contest talking about how he won’t cut taxes anytime soon? “He needs to start showing that he is the one who is best placed to keep MPs’ seats at the next election,” says an MP supporting Sunak. While Sunak is viewed as a favourite for the final two, there will be no celebrations in his camp until he is there. “A lot of MPs haven’t declared yet and we don’t know where the other candidates will swing to as they are knocked out,” says a former government adviser. The rise of Penny Mordaunt – on the second highest number of backers after Sunak – is also a cause of alarm to the other camps. Her popularity with the membership (a ConHome poll this week put her as the top choice among the grassroots) means that were she to make it to the final two she would stand a good chance of beating whomever she was up against. In order to prevent that from happening, get ready for more blue on blue. A nickname doing the rounds among MPs is Part-Time Penny, with critics alleging she has been overly picky about ministerial duties in the past: an allegation allies of Mordaunt pour cold water on. It’s a similar case with Kemi Badenoch – though her lack of cabinet experience means there is scepticism among MPs she will get that far. It’s why the right of the party is under pressure to agree on a candidate. Liz Truss is fast emerging as the preferred choice – with Brexiters including Rees-Mogg and the European Research Group chairman, Mark Francois, backing her despite the fact she voted for remain in the referendum, unlike her leadership rivals Suella Braverman and Badenoch. “Liz is the only one who can stop Rishi,” says a former adviser to the foreign secretary. It’s this pitch that is winning over wavering MPs who fear one of the lesser known or untested candidates could blow up in the final two – thereby handing the keys of Downing Street to Sunak. But Truss has opponents of her own. Several supporters of Mordaunt and Tom Tugendhat say they would row in behind Sunak if it became clear it was shaping up to be a Truss/Sunak final two. “Liz is not the answer,” says one such one-nation Tory MP. If the final two does become Truss v Sunak, prepare for a lively summer. The two will not only be offering competing visions of the economy": they will also represent two wings of the party that are increasingly hard to reconcile. It won’t be pretty. Katy Balls is the Spectator’s deputy political editor