The UK could have its third prime minister in seven weeks by Monday after Liz Truss stepped down as leader of the country’s governing Conservative Party.

Speaking outside 10 Downing Street on Thursday, Truss apologized for losing the party's trust and announced she would resign as prime minister once a new leader was chosen.

The favorite to replace her is former finance minister Rishi Sunak — but the election could also bring a sensational return to power for former Prime Minister Boris Johnson, whose supporters said he would run for office “for the good of the nation.”

Nominations for the post close at lunchtime on Monday. Nominees require the support of at least 100 Conservative MPs. If only one candidate has that level of support, they will automatically become party leaders and prime ministers.

Truss’s 45-day tenure was the shortest and most chaotic of any British prime minister. She was forced out after her economic program shattered the country’s reputation for financial stability and left many people poorer.