Sir Keir Starmer could face a fresh General Election if mutinous Labour MPs pull off a coup, allies of the PM have said.

“Friends of the Prime Minister” had warned that any new leader would “need their own mandate” from the British public, the Daily Mail reports.

Labour rules require 20 per cent of the parliamentary party, or 81 MPs, to back a new candidate to launch a formal leadership challenge.

And there are no legal requirements in place for a fresh election in order to confirm a new PM – as seen through Gordon Brown, Liz Truss and Rishi Sunak.

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But one source told the newspaper: “In the modern age, you need your own mandate…. The public hate the idea that political parties can stitch up the choice of a new PM without them.

“Anyone thinking of moving against Keir should consider that very carefully.”

Nigel Farage, whose surging Reform UK would likely take home hundreds of MPs if polling was repeated at a General Election, said last night: “This is a Government that is all at sea, without a rudder.

“The sooner we have an election, the better it will be for the country. Not that I’m holding my breath.”

Health Secretary Wes Streeting yesterday criticised a “toxic” culture in Downing Street following anonymous briefings accusing him of plotting to unseat the Prime Minister.

Sir Keir Starmer however said today that he was “assured” that “no briefing against ministers was done from No10”.

Speaking from North Wales, the Prime Minister said: “First, let me be clear that any briefing against ministers is completely unacceptable.

“That is not a new position for me, it is a position I have adopted ever since I became Prime Minister. I have made it very clear to my team.

“I have been talking to my team today. I have been assured that no briefing against ministers was done from No10, but I have made it clear that I find it absolutely unacceptable.”

He added: “I have been assured it didn’t come from Downing Street, but I have been equally clear that whether it is this case or any other, I intend to deal with it.”

Sir Keir went on to say he will “absolutely deal with” anybody responsible for briefing against ministers, Cabinet ministers or any other ministers.

No10 chief of staff, Morgan McSweeney, has been blamed by some within Labour for the fallout from the apparent ploy to warn off potential leadership contenders.

As understood by The Telegraph, Mr McSweeney had allegedly signed off briefings that sparked the Labour Party row.

Ed Miliband earlier said the Sir Keir would “get rid” of anyone behind the briefing campaign if he found them.

The Energy Secretary told Sky News: “I’ve talked to Keir before about this kind of briefing that happens. As he always says, if he finds the person, he’ll get rid of them, and I absolutely believe he would do that.”

Asked if he thought Sir Keir would sack the person, Mr Miliband replied: “Sure, yeah.”