Boris Johnson has withdrawn from the race to be Conservative leader, leaving Rishi Sunak within touching distance of becoming prime minister After senior Tories warned a Johnson comeback would lead to chaos by the end of the week, the former prime minister admitted he did not have the backing of enough MPs to lead a united party. Johnson, who never officially launched his campaign, said on Sunday night said he believed he could have delivered a Conservative victory in 2024 but it was “simply not the right thing to do” and “not the right time”. Johnson’s move piles pressure on Penny Mordaunt, the third candidate in the race, to withdraw and accept that Sunak had the support of the parliamentary party, with almost half of MPs backing him. She had only 30 public backers by Sunday night – 70 short of the number needed to get on the ballot paper. Sunak, who came second in the race against Liz Truss over the summer, racked up nominations over the weekend, ranging from rightwingers such as Kemi Badenoch and Suella Braverman to more centrist figures such as Jeremy Hunt, the chancellor, and Grant Shapps, the home secretary. He ended Sunday on more than 165 supporters including Cabinet Office minister Nadhim Zahawi, who had hours earlier heralded the return of what he termed “Johnson 2.0”. A source close to Sunak said he was “not taking anything for granted”. “Rishi will be continuing to talk to colleagues tomorrow morning before nomination papers go in, and discussing how best to unite the party and take the country forward,” the campaign source said. If he succeeds he would become Britain’s first non-white PM and, as a Hindu, his victory would be sealed on Diwali. A source on the Mordaunt campaign insisted her campaign was continuing and that she wanted to get on the ballot so party members could decide the result. “Penny is the unifying candidate who is most likely to keep the wings of the Conservative party together and polling shows that she is the most likely candidate to hold on to the seats the Conservative party gained in 2019. [Former shadow chancellor] Ed Balls, shadow cabinet ministers and Labour advisers have all said Penny is the candidate Keir Starmer fears the most.” Sunak is expected to sweep up many more Tory MPs on Monday morning given he has the momentum, but Mordaunt could win over any former Johnson supporters who want to stop him. The pair need to submit nominations by 2pm on Monday, and 150,000 Tory members will be asked to decide the result if they both get more than 100 nominations. As he dropped out of the race, Johnson claimed to have won the support of 102 colleagues – two clear of the threshold needed – but only about 60 had publicly stated their support for him. In his statement just before 9pm on Sunday, Johnson said: “There is a very good chance that I would be successful in the election with Conservative party members, and that I could indeed be back in Downing Street on Friday. “But in the course of the last days I have sadly come to the conclusion that this would simply not be the right thing to do. You can’t govern effectively unless you have a united party in parliament. “And though I have reached out to both Rishi and Penny – because I hoped that we could come together in the national interest – we have sadly not been able to work out a way of doing this. “Therefore I am afraid the best thing is that I do not allow my nomination to go forward and commit my support to whoever succeeds. I believe I have much to offer, but I am afraid that this is simply not the right time.” Earlier, Sunak launched his official campaign with a declaration that “fixing the economy” was his priority, but he gave no media interviews or formal manifesto. Mordaunt spoke to the BBC’s Laura Kuenssberg on Sunday, telling her she would be a “halfway house” between Sunak and Johnson but refused to be drawn on any economic policies or decisions on tax and spending. Labour questioned the appointment of a new prime minister while the country has heard nothing of their programme for government. Angela Rayner, the deputy leader, said: “The Tories are about to hand the keys of the country to Rishi Sunak without him saying a single word about how he would govern. No one voted for this. Perhaps it’s not surprising he’s avoiding scrutiny: after all, he was so bad that just a few weeks ago, he was trounced by Liz Truss.” Johnson’s campaign had repeatedly claimed that he had enough parliamentary support, but his critics were sceptical. A leaked WhatsApp message from his campaign manager, Chris Heaton-Harris, told supporters: “I can confirm we have completed all paperwork to be on the ballot tomorrow.” But MPs close to the rival camps of Sunak and Mordaunt said they did not believe these claims. One supporter of Mordaunt said: “We think it’s all bluffing as usual.” Johnson had gained the support of seven cabinet ministers, including James Cleverly and Nadhim Zahawi, but despite gaining some traction on Friday and cutting short his Caribbean holiday, he only added eight new public backers over the weekend. Doubts over his confidence were also fuelled after he sought deals with Sunak and Mordaunt, urging them to pull out. Prominent Conservatives had warned on Sunday that if members opted for Johnson as prime minister again, it would have spelt disaster for the party. Many MPs were concerned about the upcoming privileges committee inquiry into whether Johnson misled the Commons over the Partygate scandal – although some sources close to Johnson tried to claim that Sunak could also find the inquiry difficult to navigate. George Osborne, the former chancellor, cautioned that Johnson would have failed to command the support of the parliamentary party, even if he had the backing of the members. If Johnson had won, he warned that a political crisis would develop by the end of the week. Steve Baker – a former Truss supporter, minister and influential figure in the European Research Group faction – gave his backing to Sunak and described a comeback by Johnson as a “nailed-on disaster”. He suggested the former prime minister would make an “amazing chairman” instead. Baker told Sky’s Sophy Ridge on Sunday: “But what we can’t do is have him as prime minister in circumstances where he’s bound to implode, taking down the whole government with him. We just can’t do that again.” His view was echoed by Robert Jenrick, a former cabinet minister. Speaking to Times Radio, Jenrick said: “I cannot in good faith recommend to my parliamentary colleagues and to members of the party that we go from having the shortest prime minister in political history to the first to be expelled from the House of Commons.”