ITV News Political Reporter Shehab Khan reports on the former chancellor joining the race to succeed the PM as a growing number of Tory MPs express their support for the former chancellor
The Yorkshire MP, who this week sparked an avalanche of ministerial resignations when he quit as chancellor, said in a tweet: "I’m standing to be the next leader of the Conservative Party and your prime minister."
The frontrunner, Defence Secretary Ben Wallace, has still not decided whether to throw his hat in the ring and is consulting with friends and family as he mulls his options, ITV News Political Editor Robert Peston understands.
Mr Sunak's resignation on Tuesday, which came moments after Sajid Javid stepped down as health Secretary, eventually led to the current prime minister announcing he would stand down.
Announcing his aim to become PM, the former chancellor said: "Let’s restore trust, rebuild the economy and reunite the country."
He revealed his intentions in a three minute video which focuses on the history of his family.
He said: “I got into politics because I want everyone in this country to have those same opportunities, to be able to give their children a better future.
“Our country faces huge challenges, the most serious for a generation. And the decisions we make today will decide whether the next generation of British people will also have the chance of a better future.”
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He added: "Do we confront this moment with honesty, seriousness, and determination, or do we tell ourselves comforting fairy tales that might make us feel better in the moment but will leave our children worse off tomorrow?
"Someone has to grip this moment and make the right decisions. That’s why I’m standing to be the next leader of the Conservative Party and your prime minister."
He's already got support from senior Tory Mark Harper, who is influential among backbench Conservatives, and Oliver Dowden, the former party chair who resigned after the twin by-election defeats in June.
Mr Harper said his colleague "represents a return to traditional Conservative values and has an exciting vision for the future of our country", while Mr Dowden described the ex-chancellor as "the best person to lead our country" and beat Labour.
North Somerset Tory MP Liam Fox, a former international trade secretary, has also backed Mr Sunak.
What are Mr Sunak's chances of being selected as the new Tory leader and how is Brexit playing into the contest? Robert Peston reports
Several other MPs, including Leader of the House of Commons Mark Spencer, and ex-parliamentary private secretaries Laura Trott and Jacob Young, have also publicly backed the former chancellor, as ITV News Political Correspondent Daniel Hewitt notes.
Mr Spencer, the Conservative MP for Sherwood, said: "You have to have the experience at the highest levels of government to walk into being PM.
"Rishi has the skills, drive, answers to the big challenges and experience to deliver for the country."
Mr Sunak is drawing support from a wide range of backbenchers, including those from former 'red-wall seats' as well as more traditional Conservative heartlands.
He was later joined in the leadership race by former equalities minister Kemi Badenoch who confirmed her decision to run in The Times on Friday evening. She told the newspaper she would lower taxes alongside “tight spending” and that she wanted to run a “limited government focused on the essentials”.
Questions around Mr Sunak's loyalty have already began to emerge after it was reported that Ready4Rishi.com, a campaign website, was registered on Wednesday July 6 - the day before Mr Johnson resigned party leader.
Robert Peston found evidence that the similarly-named ReadyForRishi.com, which redirects to Ready4Rishi.com, was registered last December.
"On the face of it, Sunak - who only became an ex chancellor on Tuesday - has been quietly preparing his leadership bid for a while," he writes.
Mr Sunak, 42, was a rising star of the Tory party after becoming the UK's chancellor in early 2020 by bringing in financial support during the pandemic, including the furlough scheme.
Which of the prospective candidates are popular with grassroot Tories? ITV News Social Affairs Correspondent Sarah Corker reports from Yorkshire
But his popularity waned through numerous controversies, such as his fine for breaking Covid rules and the furore involving his wife's tax status.
Even before he made his formal announcement, Mr Sunak had come under fire from Johnson loyalists, with Brexit Opportunities Minister Jacob Rees-Mogg denouncing him as a “high tax chancellor” who failed to curb inflation.
He's been criticised for his fiscal policy, which has seen him bring in tax increases and resist providing additional cash support for struggling families.
Despite that, he is still considered one of the favourites to become the next prime minister, behind Mr Wallace.
There are more than a dozen MPs who have either announced their intentions or thought to be considering a run.
Attorney General Suella Braverman launched an unlikely leadership bid as support for Mr Johnson crumbled around him on Wednesday night. Ms Braverman, who was first elected as an MP in 2015, is regarded as something of an outsider for the leadership given the party grandees already tipped to be in the running.