Britain's Ex-Chancellor Rishi Sunak launches bid to be Conservative leader
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.
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".