Liz Truss has resigned as the UK prime minister after 45 days in office. She will become the shortest-serving PM in British history when she stands down.
Her term has been marked by turmoil. Her exit has triggered a second Tory leadership election in just four months.
Truss said her successor would be elected by next week after a rebellion by Tory MPs forced her to quit, the BBC reported.
Boris Johnson is among MPs said to be considering bids but Chancellor Jeremy Hunt has ruled himself out, the report added.
Tory MPs revolted against Truss after her series of U-turns on promised economic plan that sapped her of authority.
In a brief speech outside Downing Street on Thursday, Truss said the Conservative Party had elected her on a mandate to cut taxes and boost economic growth.
But given the situation, she said: “I recognise that I cannot deliver the mandate on which I was elected by the Conservative Party.”
Labour leader Sir Keir Starmer and other opposition parties called for an immediate general election following Truss’s resignation speech. She will remain in post until a successor formally takes over as party leader and is appointed prime minister by King Charles, the BBC said.
None of the candidates who stood against Truss in the previous contest have indicated whether they would stand.
However, Conservative sources have told the BBC that Business Secretary Jacob Rees-Mogg has been encouraging colleagues to back Johnson in the race.
Sir Graham Brady, the chairman of the 1922 committee of backbench Conservative MPs, said a new leader could be chosen by next Friday.
Under party rules, leadership hopefuls will need to secure the support of 100 MPs in order to enter the contest – this means a maximum of three candidates can stand.
A first ballot will be held among MPs and the person with the lowest number of votes will be eliminated, if there are three candidates. If a second ballot is needed, MPs will be able to signal who they prefer through an indicative vote. And if both candidates opt to stay in the race, the final decision will go to party members via an online vote, the BBC explained.
Leaders of allied nations thanked Truss for her co-operation, including US President Joe Biden and French President Emmanuel Macron, who said he wanted “stability” from the next UK prime minister.
In her speech, Truss said she entered “office at a time of great economic and international instability”, as war rages in Ukraine and living costs skyrocket. She said her government delivered on providing support for energy bills and reversing a rise in National Insurance, a tax on workers and companies.
Her resignation comes after a period of political and economic turbulence, which forced her government to ditch tax cuts that sent financial markets into a tailspin. She sacked close political ally Kwasi Kwarteng as chancellor and appointed Hunt as his successor as she attempted to calm the markets.
At PM’s Questions on Wednesday, Truss insisted she was a “fighter, not a quitter” after Labour’s leader asked her why she had not resigned. However, more instability followed, when Suella Braverman quit as home secretary and a vote on fracking fell into disarray, with some Tory MPs accused of bullying.
Truss’s resignation sets off a scramble to find a successor to lead a deeply divided party, which is lagging behind Labour in the polls after 12 years in power.
Candidates who contested the last leadership election earlier this year included Ms Braverman, International Trade Secretary Kemi Badenoch, Commons Leader Penny Mordaunt, and former Chancellor Rishi Sunak.
Former prime minister, Theresa May said “MPs must now be prepared to compromise. It is our duty to provide sensible, competent government at this critical moment for our country.”
The next general election is not due to take place until at least 2024, after the Conservatives won a landslide majority in the last one in 2019.