The Prime Minister has faced a grilling over the “toxic culture” in No10 as a civil war erupted at the heart of the Labour Party.
Sir Keir Starmer condemned "completely unacceptable" briefings against his Health Secretary Wes Streeting at Prime Minister’s Questions on Wednesday.
Mr Streeting this morning accused Downing Street insiders of trying to “kneecap” him as Labour went into a frenzy over talk of a coup to topple Sir Keir.
The PM insisted he has "never" approved attacks on his cabinet ministers, as he was asked whether he has full confidence in his chief of staff Morgan McSweeney.
✍ Comment: Why is Keir Starmer so unpopular?
Conservative Party leader Kemi Badenoch asked if Mr Streeting was right when he said there was a "toxic culture in Downing Street that needs to change".
Sir Keir replied: "My focus each and every day is on rebuilding and renewing our country. But let me be absolutely clear, any attack on any member of my cabinet is completely unacceptable."
He said Mr Streeting had out-performed expectations by delivering five million extra appointments within the first year of a Labour government, higher than the two million pledged.
"He's doing a great job, as is the whole of my Cabinet," Sir Keir said.

Ms Badenoch said: "Just last night, [Sir Keir’s] allies accused not just the Health Secretary but the Home Secretary and even the Energy Secretary of launching leadership bids.
“These attacks came from No10, nowhere else, his toxic Number 10. The person responsible for the culture in Number 10 is his chief of staff Morgan McSweeney. Does the Prime Minister have full confidence in him?"
Sir Keir replied: "Morgan McSweeney, my team and I are absolutely focused on delivering for the country. Let me be clear, of course, I've never authorised attacks on cabinet members, I appointed them to their post because they're the best people to carry out their jobs."
Mr Streeting was forced to hit out after allies of the Prime Minister briefed that Sir Keir would fight any attempt to oust him.
Supporters of the Health Secretary and Home Secretary Shabana Mahmood were said to be on “manoeuvres” ahead of a possible leadership challenge.
Some of the new intake of Labour MPs were described as “feral” by a Cabinet minister who backs Sir Keir staying in No10.
Ms Badenoch accused the Prime Minister of having lost control of No10.
She stressed: "[Sir Keir] says these attacks aren't authorised. That means he's lost control of Number 10, because that's where they're coming from. The real scandal is that two weeks from a budget, the Government has descended into a civil war, instead of fixing the economy the mess they've made of the economy.”
Sir Keir was met with laughter from the opposition benches when he insisted that the Government was a "united team". He added: "The Bank of England has upgraded growth today, we've secured £230 billion of private investment."
As the coup rumours swirled, Mr Streeting was asked on BBC Breakfast: “Are you a Faithful or are you a Traitor?”

He responded: “Someone has definitely been watching too much Celebrity Traitors in Downing Street, they should swap it for CountryFile in future and calm down a bit.
“I’m a Faithful, what you have seen from a silly No10 source overnight is probably the worst attack on a Faithful since Joe Marler was banished in the Traitors’ final.”
Appearing earlier on the morning media round, Mr Streeting, MP for Ilford North, was bombarded with questions about a possible plot to oust Sir Keir, strongly denying that he was involved.
He slammed what he called a “toxic” culture in Downing Street.
He also turned on No10 sources accusing them of “self-defeating and self-destructive behaviour” by fuelling the story about a possible coup and distracting from other messages such as attempts to improve the NHS.
“I do think that going out and calling your Labour MPs feral is not very helpful,” he told Sky News.
“Trying to kneecap one of your own team when they are out not just making the case for the Government but actually delivering the change that we promised, I think that is also self-defeating and self-destructive behaviour.
“I also think whoever did this does not speak for the Prime Minister.”
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."

He said the Downing Street briefing was distracting from Labour’s attempts to get across to voters that it is delivering change including cutting NHS waiting lists, which are still over seven million.
“We are going to spend more time...on a totally irrelevant and untrue process story, but also a self-defeating one because it has come from Downing Street,” he added.
UK Government borrowing costs ticked higher on Wednesday morning, as the price of gilts, UK Government bonds, slipped in value amid the speculation over a leadership challenge to Sir Keir which could also see Chancellor Rachel Reeves ousted.
Yields on 10-year-gilts, which move counter to the price of the bonds, rose by 3 basis points to 4.42% in early trading. The yield on the longer-term 30-year-gilt also rose by a similar amount.
The rise come after yields had dropped significantly on Tuesday after rising unemployment and falling wage growth prompted predictions of interest rate cuts.
The value of the pound also moved 0.02% higher to 1.315 against the dollar.
Reporting over the last week has suggested a growing number of Labour MPs are unhappy with the Prime Minister’s performance and the party’s poll ratings, and are plotting a coup.
The Budget is also reportedly proving unpopular, with backbenchers anxious about the prospect of tax rises which break the party’s manifesto commitments.
The Prime Minister’s senior political aides are said to have warned attempts to oust him will lead to market chaos, and would upend international relations and the Labour Party.
An evening flurry of briefings from No 10 came as part of a ploy to put down several senior Labour figures who are said to be “on manoeuvres” to supplant Sir Keir.

No 10 has singled out the Health Secretary to warn off other potential leadership challenges from senior Labour figures including Ms Mahmood and Energy Secretary Ed Miliband, reports said.
However, one critic within Government told several news outlets No10 had gone into “full bunker mode, turning on their most loyal Cabinet members for absolutely no reason”.
“A circular firing squad won’t help the Government out of the hole we’re in,” they added.
Challengers for the Labour leadership can initiate an election with the 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 the ballot alongside individual members.