Who will be the UK's next prime minister? Here are the potential candidates

LONDON -- Liz Truss announced her resignation on Thursday after only 45 days in office, making her the shortest-serving U.K. prime minister in history.

Her resignation follows weeks of political and economic turmoil after her government introduced a "mini-budget" that sent financial markets into crisis and cratered the value of the Great British Pound.

As a result, members of the Conservative Party's 1922 Committee, the ruling group that sets out leadership contest rules, have introduced immediate changes to the process as the party prepares to name its third prime minister in two months.

Potential prime ministerial candidates will need the support of at least 100 fellow Members of Parliament to secure their spot on the ballot to become the next party leader.

The Conservative Party currently has 357 members in Parliament meaning there will be a maximum of three leadership candidates that could be put forward.

The increased threshold of MPs needed to support a candidate for office "can be achieved by any serious candidate with a chance of going through" Sir Graham Brady, Chairman of the 1922 Committee, said on Thursday.

Many see these changes as an attempt to bypass the Conservative Party's internal membership voting in the leadership contest and, as a result, could produce another leader who creates further political and economic instability.

Former Prime Minister Boris Johnson is speculated to make a dramatic return to the frontline of British politics only 6 weeks after he reluctantly resigned amid intense scandal. He remains popular with Conservative Party members but is seen as a liability by many of his fellow colleagues.

On the potential return of Johnson, John Baron, MP for Basildon and Billericay, told the BBC that "we've now got to look forward and pick a new candidate, somebody who has credibility, experience and can unite the party."

Johnson has not yet confirmed if he is standing for office again but will be flying back to the U.K. this weekend after enjoying a vacation in the Caribbean.

Former Finance Minister Rishi Sunak is seen as another likely candidate after he came second to Liz Truss in this summer's leadership contest. Sunak repeatedly warned Truss that her economic plans and proposed tax cuts would create economic turmoil. The subsequent financial fallout looks to have proven him correct.

Sunak is a potential calming voice and remains the U.K.'s seventh most popular politician, according to analytics firm, YouGov. However, reports that his wealthy family used non-domiciled status to reduce their tax payment is seen as a potential gift to Labour, the U.K.'s opposition party, amid the current cost of living crisis.

Penny Mordaunt, who placed third in the leadership contest, is another likely favorite.

Mordaunt served as former Prime Minister Theresa May's defense secretary, the first woman to hold the post in British history, and her previous experience within the Ministry of Defense could be a vital benefit when it comes to how the U.K. deals with the war in Ukraine.

Suella Braverman, the former Interior Minister -- who lasted a day less in office than Liz Truss did -- is another probable contender for the top job.

A renowned anti-immigration and Brexit supporter, Braverman proposed strengthening the punishment for possessing cannabis and is seen as the preferred candidate for the ideological right of the Conservative Party.

Across the aisle, however, Leader of the U.K.'s Opposition Party, Sir Keir Starmer, has joined other political leaders from the minority parties in calling for a general election.

"The British public deserve a proper say on the country's future" and "we need a general election," he said on Twitter.

The next prime minister will be announced by Oct. 28.