Rishi Sunak has entered the race to be the next leader of the Conservative Party and prime minister.
The former chancellor is the most high profile figure so far to announce his candidacy.
His resignation from the cabinet on Tuesday helped trigger the mass walkout of ministers that forced Boris Johnson to stand down as Tory leader.
Mr Johnson intends to stay on as prime minister until the Tory party chooses a successor.
Senior backbencher Tom Tugendhat and Attorney General Suella Braverman have already announced their plans to stand.
Meanwhile, former Foreign Secretary Jeremy Hunt, Defence Secretary Ben Wallace, and Former Health Secretary Sajid Javid are said to be considering leadership bids, while former Brexit minister Steve Baker has signalled he will mount a challenge.
A timetable for the Tory leadership race is due to be confirmed next week and the new prime minister is expected to be in position by September.
'Ready for Rishi'
Announcing his decision to stand in
a social media video, Mr Sunak said he wanted to "restore trust, rebuild the economy and reunite the country".
He added: "Someone has to grip this moment and make the right decisions."
"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," he asked.
He promised "to lead this country in the right direction" based on values of "patriotism, fairness and hard work".
He said the country faced "huge challenges" and that decisions today would determine whether the next generation got "the chance of a better future".
Pointing to his credentials to be leader, Mr Sunak said he had run the "toughest department in government during the toughest times when we faced the nightmare of Covid".
Several senior Tory MPs have endorsed Mr Sunak's candidacy, tweeting their support and promoting his campaign slogan "Ready for Rishi".
Commons Leader Mark Spencer
wrote: "Rishi is the leader that can unite the Party, bring the whole country together and win us that fifth general election victory."
Mr Sunak, 42, was an analyst for the investment bank, Goldman Sachs, and was later a partner in two hedge funds, before becoming an MP for the North Yorkshire constituency of Richmond in 2015.
He was once seen as the leading contender to succeed Mr Johnson as Conservative Party leader and prime minister.
Appointed chancellor in July 2020, Mr Sunak had to grapple with the consequences of the Covid-19 pandemic, spending huge amounts to keep the economy afloat.
But his reputation was dented by
a controversy over his wife's tax affairs and being fined for breaching lockdown rules during the pandemic.
Mr Sunak was fined by the Metropolitan Police, along with Mr Johnson and his wife Carrie, for breaching Covid rules by attending a birthday party for the prime minister in June 2020.
A backer of Brexit, Mr Sunak was loyal to Mr Johnson, despite tensions over economic policy and the prime minister's wish to cut taxes more quickly as living costs rise.
But their relationship ultimately broke down when Mr Sunak dramatically resigned in tandem with close ally and former Health Secretary Sajid Javid.
In his resignation letter, Mr Sunak said "the public rightly expect government to be conducted properly, competently and seriously".
Mr Sunak also referenced tensions over the economy in his resignation letter, telling the PM their approaches had become "fundamentally too different".
His resignation and that of Mr Javid triggered a mass exodus of ministers and precipitated the downfall of Mr Johnson's government.
https://www.bbc.co.uk/news/uk-politics-62099272