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 admitted having lost the faith of the party, and said she would quit as prime minister when a new leader was elected.

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 leader and prime minister.

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.

She had promised tax cuts funded by borrowing, deregulation and a sharp shift to the right on cultural and social issues.

But within weeks she was forced to sack her finance minister and closest political ally, Kwasi Kwarteng, and abandon almost all her economic program after their plans for vast unfunded tax cuts crashed the pound and sent British borrowing costs and mortgage rates soaring.

Approval ratings for her and the party collapsed. On Wednesday she lost the second of the government’s four most senior ministers, deepening the sense of chaos at Westminster.

Truss’s humiliation was complete when a British tabloid newspaper live-streamed a photo of the prime minister alongside a lettuce bought from a supermarket, and asked readers to guess which would have the longer shelf life. The lettuce won.