Rishi Sunak has formally announced his bid to replace Liz Truss as prime minister.
The former chancellor said he would lead with “integrity, professionalism and accountability” in an apparent attempt to contrast himself with his predecessors as his backers warned a Boris Johnson comeback would be a “guaranteed disaster”.
He tweeted on Sunday morning: “The United Kingdom is a great country but we face a profound economic crisis.
“That’s why I am standing to be leader of the Conservative Party and your next prime minister.
“I want to fix our economy, unite our party and deliver for our country.”
Declaring his prime ministerial ambitions, Sunak wrote: “I served as your chancellor, helping to steer our economy through the toughest of times.
“The challenges we face now are even greater. But the opportunities, if we make the right choice, are phenomenal.
“I have the track record of delivery, a clear plan to fix the biggest problems we face and I will deliver on the promise of the 2019 manifesto.
“There will be integrity, professionalism and accountability at every level of the government I lead and I will work day in and day out to get the job done.
“I am asking you for the opportunity to help fix our problems. To lead our party and country forwards towards the next general election, confident in our record, firm in our convictions and ready to lead again”.
Sunak was defeated in the last Tory leadership race as the party membership picked rival Truss, garnering 60,399 votes to her 81,326.
In that contest, he positioned himself as the candidate prepared to tell hard truths about the state of the public finances rather than “comforting fairy tales”.
He remained resolute in the view that his rival’s promises of unfunded tax cuts at a time of worsening inflation were irresponsible, dangerous and un-Conservative, predicting that they would lead to surging mortgage rates.
After Truss took office, her disastrous mini-budget triggered turbulence in the financial markets and forced the Bank of England to intervene, proving Sunak right.
Sunak joins Penny Mordaunt in the race to be the next prime minister, after she became the first candidate to put her name forward in the leadership contest.
However, Boris Johnson has also returned to the UK to plot a second run for the top job, in a move that has divided opinion among Conservative MPs including his former allies.
Candidates require the backing of 100 MPs in order to make the cut to become the next leader of the Conservative Party, and in turn the new prime minister.
Tory MP Sir James Duddridge tweeted on Saturday that Johnson now has more than the 100 backers needed to enter the contest, although public declarations for the former PM are much lower than that number.
Jacob Rees-Mogg was adamant on Sunday that Johnson will stand in the Tory leadership race.
The business secretary, a staunch ally of Johnson, told the BBC’s Sunday With Laura Kuenssberg programme: “I have been speaking to Boris Johnson, and clearly he’s going to stand, there’s a great deal of support for him.”
But shadow communities secretary Lisa Nandy said even considering bringing Johnson back as prime minister is a sign of “absolute utter desperation”,
She told Sophy Ridge On Sunday: “I wouldn’t trust Boris Johnson to run a bath, let alone run the country.
“He degraded and debased our politics. He lost all of that goodwill from the country and from his own colleagues in a very short space of time.
“It’s extraordinary watching Tory MPs who put in letter of no confidence in him just a few weeks ago saying he wasn’t fit to hold the highest office now talking openly about trying to bring him back. It is a sign of absolute utter desperation in the Tory party.”
Labour leader Sir Keir Starmer repeated his call for a general election, telling BBC One’s Sunday With Laura Kuenssberg: “The country needs change, the country needs stability, the country needs to get rid of this chaos, it’s been going on for the best part of 12 years, we don’t need another change at the top of the Tory party, we need a change of government.”
Tory MPs will vote on Monday, and two candidates will be put forward to the Tory membership unless one pulls out, with a result being announced on Friday.
Candidates have until 2pm on Monday to secure the 100 nominations, limiting the ballot to a maximum of three candidates.
Scottish Conservative chairman Craig Hoy insisted on Sunday the party could serve out its full five-year term in government at Westminster.
But he conceded the Tories have “to take some of the blame” for the “political instability” in the UK.
He told STV News: “There is no doubt that there is a frustration in the country at the events we’ve seen in Westminster.
“That’s why this week is an opportunity for us to come together behind a new leader and to focus on the people’s priorities. And top among them is to make sure that we help hard working households through what will be a very difficult winter ahead.
“And that’s precisely what we will do.”