British health minister Wes Streeting said any talk of a challenge against Prime Minister Keir Starmer was not true, adding that he supported him.
He said he was confident Mr Starmer would lead the Labour party into the next general election in 2029.
The Health Secretary categorically denied that he was plotting to oust Mr Starmer, comparing suggestions he would do so to conspiracy theories.
Mr Starmer steered his Labour Party to one of the biggest election victories in British history in 2024 but just 16 months later it is languishing in the polls and poised to break one of its main election pledges to increase income taxes for the first time since the 1970s.
Several British media outlets cited allies of Mr Starmer saying the prime minister would fight any challenge to his leadership, with Mr Streeting and interior minister Shabana Mahmood named as possible candidates to replace him.
Doing the early media round of talking to broadcasters, Mr Streeting said the briefings of a challenge were self defeating because they gave the impression Mr Starmer was fighting for his job when he was instead focused on fighting to improve Britain.
Mr Streeting attacked whoever was responsible for the rumours, suggesting they had been "watching too much Celebrity Traitors".
He told Sky News: "This is just about the worst attack on a faithful I've seen since Joe Marler was kicked out and banished in the final.
"It's totally self-defeating briefing, not least because it's not true and I don't understand how anyone thinks it's helpful to the Prime Minister either."
"I'm not going to demand the prime minister's resignation," he said. "I support the prime minister. I have done since he was elected leader of the Labour Party."
Opinion polls suggest Mr Starmer is one of the most unpopular prime ministers of all time, and his party has trailed Nigel Farage's Reform UK party for months.
The Labour Party is now bracing for the budget on 26 November, with Chancellor of the Exchequer
Rachel Reeves suggesting she will have to increase taxes to fill a fiscal black hole, a year after she hiked levies by £40 billion in what she said was a one-off event.
Reporting PA, Reuters
