Keir Starmer has attempted to draw a line under extraordinary briefings by his allies that No 10 feared Wes Streeting could launch a leadership coup, insisting he had been reassured it “didn’t come from Downing Street”.The prime minister gathered his senior staff to stress that briefings against cabinet ministers were “unacceptable” after apologising to Streeting for what had happened on Wednesday.However, his spokesperson said Starmer also accepted assurances that No 10 staff had not briefed against Streeting and that he stood by his chief of staff, Morgan McSweeney.Since the furore over No 10’s fears about a leadership challenge from Streeting, first revealed by the Guardian on Tuesday, there had been calls from Labour MPs for McSweeney’s resignation.One senior Labour source described McSweeney as “the great survivor” after the Downing Street gathering.

Some senior ministers including the chancellor, Rachel Reeves, had suggested there could be a leak inquiry into the briefings about the threat of a leadership challenge.However, Starmer appeared keen to bring an end to the episode without launching a formal investigation, while warning his aides about “the high standards that he expects from staff, and if anyone falls below those standards there will be consequences”.Streeting, who was linked by some sources as the most likely plotter against Starmer, is also understood not to be pressing for the departure of McSweeney.The health secretary dismissed the row as “yesterday’s news”.The prime minister apologised to the health secretary in a brief phone call with him late on Wednesday in which Streeting did not bring up McSweeney by name.

The Guardian reported that, in private meetings with MPs on Wednesday, the prime minister stood by McSweeney and would not directly commit to any consequences for those who had briefed the newspapers.Starmer spoke to senior Downing Street staff on a video call on Thursday morning to stress that “briefings against cabinet ministers are completely unacceptable”, his deputy spokesperson said, adding that “the prime minister said he had been assured that no No 10 staff briefed against ministers” and that he accepted the assurances.Asked why Starmer had apologised to Streeting if he did not believe the health secretary had been briefed against by No 10, the spokesperson said the PM had “apologised for the situation that the health secretary was in”.Starmer, in a TV clip recorded during a visit to north Wales, told broadcasters he had warned his team against such briefings.He said: “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.

”Asked if he would sack anyone found to have briefed, Starmer said he would “absolutely deal with anybody responsible for briefing against ministers”.One senior Labour source said they expected MPs would eventually turn their attention back to the budget – as well as significant immigration plans to be announced by the home secretary, Shabana Mahmood, this week.Sign up to First EditionOur morning email breaks down the key stories of the day, telling you what’s happening and why it mattersafter newsletter promotionThe energy secretary, Ed Miliband, said he believed Starmer would not have authorised any of the personal attacks, but said briefing was a “longstanding aspect of politics”.“I’ve talked to Keir before about this kind of briefing that happens and as he always says, if he finds the person, he’ll get rid of them.And I absolutely believe he would do that,” he told Sky News.

Reeves also insisted she had confidence in McSweeney and that there was “no evidence” of briefing against cabinet ministers.The chancellor suggested there would be a leak inquiry, though No 10 suggested the prime minister had already accepted assurances from his staff that they were not briefing against Streeting.“The prime minister was really clear yesterday that there is no place for that sort of briefing and that sort of behaviour, and I absolutely agree with the prime minister,” Reeves said.Cabinet ministers had been among those privately calling for McSweeney to be sacked in the aftermath of the story.But, on Thursday, several ministers said they were prepared to draw a line under the row.

“I still think it’s a question of when, not if [there is a leadership challenge],” one said.Another senior MP said: “The only person who has emerged well out of this is Wes, which cannot have been the intention of those briefing.”MPs who spoke privately to Starmer on Wednesday said they believed the prime minister when he insisted he had not authorised the briefings.But another said it had been a test of resolve as to whether Starmer was prepared to root out who was briefing.“I don’t know what else we can say to him if he can’t even pretend those responsible will be sacked – he’s made Wes a martyr and there’s lots of people here saying how good he was on the radio,” said one MP who saw the prime minister on Wednesday.

Another Labour source said that MPs who obsessed about the briefings were “asking the wrong questions”.“The drift in direction is the real government killer, not briefings.The question that should be worrying everyone is – why does this government feel so panicked and under siege? Because if they are, then we all are.”