Sir Keir Starmer has been mocked for being in office “but not in power” as his floundering leadership plunges into further chaos. An extraordinary civil war continues to rage inside No 10 and at the top of the Labour Party following an alleged plot to remove him from office.

It has left the Prime Minister facing demands to sack his closest aide for a bungled bid to kill off the supposed leadership threat by Wes Streeting. The Health Secretary denied claims that he was planning a coup and attacked a “toxic” culture in Downing Street.

Sir Keir gave a lukewarm backing to Morgan McSweeney, his long-time ally and chief of staff.

The humiliating saga, which comes less than a fortnight before a crunch Budget, has left Sir Keir severely weakened after a disastrous 15 months as Prime Minister.

Conservative leader Kemi Badenoch said: “The Prime Minister has shown he is in office, but not in power.”

She added: “Two weeks before the Budget, this Prime Minister has lost control of his Government.

“He’s lost the confidence of the Labour Party. And he’s lost the trust of the British people.”

The pound dropped to its lowest level in more than two years on Wednesday as speculation over the Prime Minister’s future erupted.

It is the second alleged plot to oust the PM in as many months, after it was claimed Manchester Mayor Andy Burnham was planning a move against him.

Sir Keir was forced to condemn “completely unacceptable” attacks on Mr Streeting during Prime Minister’s Questions.

He claimed his Cabinet is “united” and that the Health Secretary “is doing a great job”.

The Prime Minister told MPs that he had “never authorised attacks” on Cabinet ministers.

Senior No 10 sources said Sir Keir would fight any leadership challenge but suggested the briefing against Mr Streeting had not come from Downing Street.

Mr Streeting called for anyone behind the “juvenile” briefing against him to be sacked as he complained about the culture within Sir Keir’s administration.

His criticism of the No 10 operation focused fresh attention on Mr McSweeney, the mastermind of Labour’s 2024 election success.

Facing off against the PM in the Commons, Mrs Badenoch said “the Government has descended into a civil war” and asked Sir Keir to say whether he still had full confidence in Mr McSweeney.

“Morgan McSweeney, my team and I are absolutely focused on delivering for the country,” Sir Keir told her.

“I’ve never authorised attacks on Cabinet members. I appointed them to their posts because they are the best people to carry out their jobs.”

Mr Streeting gave a series of broadcast interviews on Wednesday morning before speaking at a health conference.

He criticised whoever was responsible for the rumours, suggesting they had been “watching too much Celebrity Traitors”.

Mr Streeting told BBC Radio 4’s Today: “There are people around the Prime Minister who do not follow his model and style of leadership.

“I can tell you, without having even spoken to the Prime Minister, what he thinks of briefing, what his reaction will be to the front pages and the broadcast bulletins overnight and the words I’m sure he would use are not suitable for a family show like this.”

Asked if he should sack those responsible, Mr Streeting said: “Yes. But he’s got to find them first and I wouldn’t expect him to waste loads of time on this.”

Quizzed at an NHS conference in Manchester if he would fight alongside Sir Keir if there were any plots to oust him as PM, Streeting said: “Yes.”

“The bizarre thing about some juvenile briefing overnight is it’s people in No 10 who’ve said the PM is fighting for his job,” he said.

“I don’t think that’s a helpful or constructive thing to say, I also don’t think it’s true,” he added.

Asked whether he thought Mr McSweeney was responsible for the culture in Downing Street, Mr Streeting said: “I am not going to add to the toxic culture by contributing to the toxic culture and going after individuals.

“I don’t think that is a constructive or positive thing to do.

“One thing I would say for Morgan McSweeney is there wouldn’t be a Labour government without him.”

The unrest at the top of the party comes after Labour’s poll ratings have plummeted since Sir Keir delivered a landslide General Election victory in July 2024.

Rachel Reeves’s Budget in a fortnight could see the party rip up its manifesto promise not to increase income tax, and MPs fear a bloodbath in elections next May in English councils and the Scottish and Welsh parliaments.

One fed-up Labour MP told the Daily Express: “I was hoping things can only get better. How wrong I was.”

There is a high bar to launch a leadership challenge against the Prime Minister.

A challenger for the Labour leadership can only initiate an election with the public support of 20% of the party’s MPs, which currently means 80 nominations would be needed.

Labour affiliates, including the trade unions, would be able to vote in any subsequent ballot alongside individual members.