Sir Keir Starmer is due to hold talks with Wes Streeting in Downing Street on Wednesday morning as he fights on in an increasingly tough battle to remain Prime Minister.
The meeting, first reported by The Times, will fuel speculation that the Health Secretary is about to launch a leadership challenge against Sir Keir.
The talks come after another bruising day for the Prime Minister as four ministers quit from his Government and more than 90 of his MPs publicly called for him to go.
Sir Keir’s chances of survival seem to be slipping away as he struggles to contain the revolt from within his party.
Labour descended into deeper civil war over the PM’s future, as more than 100 came out against those in the party calling for him to go and warned against a leadership contest.
It is understood that Mr Streeting, seen as a likely leadership rival, will not say anything after the meeting that could distract from the King’s Speech and the State Opening of Parliament.
The Times said he is expected to discuss the “turbulence” gripping the party and how Sir Keir will “get us out of this mess”.
Prominent MP Jess Phillips and health minister Zubir Ahmed, an ally of Mr Streeting, were among the junior ministers to exit the Prime Minister’s Government, piling pressure on him to go.
The Labour leader vowed to fight on at Tuesday’s Cabinet meeting, and was publicly backed by several ministers at the top of Government, including his deputy David Lammy, who urged colleagues to “step back and take a breath”.
Despite speculation that Home Secretary Shabana Mahmood could resign after reports that she privately told the Prime Minister to consider his position, a spokesman said she was “cracking on with the job” and would not be quitting.
A statement understood to have been signed by more than 100 Labour MPs, and not organised by Downing Street, urged colleagues to come together behind the Prime Minister.
The statement said: “Last week we had a devastatingly tough set of election results. It shows we have a hard job ahead to win back trust from the electorate.
“That job needs to start today – with all of us working together to deliver the change the country needs.
“We must focus on that. This is no time for a leadership contest.”
At least 92 out of Labour’s 403 MPs have demanded Sir Keir’s departure after the party’s electoral mauling last week, passing the threshold to trigger a leadership contest but without meeting the condition that they all line up behind a single challenger.
Ms Phillips, the most high profile of the ministerial departures, criticised the Prime Minister’s failure to be “bold”.
Mr Ahmed followed her out of the door on Tuesday afternoon, citing a “lack of values-driven leadership” and saying the public has “irretrievably lost confidence in you as Prime Minister”.
Alex Davies-Jones, believed to be a supporter of Mr Streeting, also quit the Home Office, saying there had been a lack of “bold, radical action”.
Resigning housing minister Miatta Fahnbulleh, an ally of Energy Secretary Ed Miliband, said the public had lost trust in Sir Keir because of issues such as the scrapping of the winter fuel payment.
The Prime Minister earlier defied calls to vacate No 10, telling his Cabinet the country “expects us to get on with governing” and “that is what I am doing”.
He avoided being directly challenged as he declined to discuss his leadership during Tuesday’s gathering or meet critics individually afterwards, PA understands.
Sir Keir said he would only speak to ministers one-to-one about his fate, but did not do so once Cabinet concluded, according to sources.
Downing Street’s readout said ministers had agreed that the “number one priority remains getting the Strait of Hormuz open again” as they discussed the Iran war in the meeting.
The Prime Minister chaired a Middle East Response Committee at lunchtime as planned, and he later met construction apprentices during a visit in London, although no reporters were invited.
A meeting scheduled for Tuesday afternoon between the Prime Minister and leaders of the unions affiliated to Labour – the so-called Tulo group – was cancelled.
Speaking to reporters outside No 10 later, Mr Lammy warned that “navel-gazing” within Labour would only benefit Nigel Farage’s Reform UK, which made stunning gains at the expense of the ruling party in last week’s elections.
“(The Prime Minister) was elected just under two years ago with a mandate from the British people for five years. He has my full support,” said the Deputy Prime Minister, who is also Justice Secretary.
“No one seems to have the names to stand up against Keir Starmer, and for those who are suggesting that he should stand down, they should say which candidate would be better.”
He added: “I urge colleagues to step back and not benefit Nigel Farage and Reform.”
Greater Manchester’s Andy Burnham, who is widely regarded as a key challenger to be PM, could meet with Sir Keir Starmer on Wednesday, it has been suggested.
The Mayor of Greater Manchester was seen in London on Tuesday where he has been meeting Labour MPs about a leadership bid, Labour sources have said.
Speaking to Sky News, former home secretary Lord Blunkett said: “I've no reason to believe that Keir Starmer wouldn't talk to Andy Burnham. Why would he not?”
As Burnham is a mayor and not a Member of Parliament (MP), he is currently not eligible to stand for PM, which presents a major obstacle to any potential leadership bid.
But his supporters are reportedly pushing for Starmer to set a resignation timetable that would allow Burnham enough time to trigger and win a parliamentary by-election.
To find a path back to Westminster, Burnham must first find a vacant seat, which would require a sitting MP to resign. He would then need to convince the National Executive Committee (NEC) to allow him to run, before then securing a by-election victory.
If he makes it to Parliament, Andy Burnham could then throw his hat in the ring.
