"Every morning when he wakes up, it's been the same two questions. Does Wes have the numbers? And does Andy have a seat?"
An ally of the prime minister tells me for several months those have been No 10's preoccupations. The answer to the first is still disputed - Wes Streeting's team says "Yes". Team Starmer says "No way".
But it's become academic because Streeting has quit government to prepare for a run at the top job. And then, a frenzied No 10 discovered on Thursday morning that Andy Burnham, the mayor of Greater Manchester, had found an MP willing to give up their seat so he can take a crack at it, the start of his long-anticipated attempt to make it to No 10. It might not be official, but the contest to replace the prime minister is on.
You might agree with one cabinet minister who told me "the public are pretty horrified" that Labour is tumbling into replacing its leader. Or you might share the view of another minister who reckons the public's message from the ballot boxes last week "just had to be respected".
In a messy and angry way, Labour's tribes have reached a decision - that it's about time a contest to replace Sir Keir Starmer got under way. But there are plenty of choices that still face him - decisions that affect us all, and one vital one that he alone must make.
If everything goes according to the challengers' plan, a leadership contest seems likely over the summer, and a new leader and prime minister by the party conference in late September. That means that even if Starmer is on his way out, he will still have a chunk of time in office.
Note that this timetable is miles away from being confirmed.
There is already a debate at the top levels of Labour over whether there will be a contest at all. If Burnham wins the by-election, one minister tells me he and Streeting should find an "accommodation" to avoid what could be a "catastrophic" leadership contest. Another senior figure predicts no-one would even stand against Burnham because he has so much momentum, "he'll be carried south for a coronation". That could mean a new resident in No 10 more quickly.
It's fair to say this view is not universal - others in government are furious with Burnham, and believe strongly there has to be a contest so the party can thrash out its differences.
But nor can it be said enough that Andy Burnham might not be successful in his bid to become an MP again. Reform will throw everything they have at winning the Makerfield seat to stop him in his tracks. They are flush with cash and still leading in the polls. For all Burnham's personal popularity, Labour is neither popular nor rich right now.
I asked a minister what would happen if the so-called King of the North didn't win - their answer was best described as a painful sigh. Would Burnham's support switch over to Angela Rayner? Would some MPs panic and swarm back to Starmer? Despite the thundering hooves of the herd moving away from the party leadership this week, it's 2026, so don't rule anything out.
Whatever happens, Starmer has vital time ahead in No 10 when there are conflicts abroad and intense pressures all around. World events don't just stop because the governing party in one country or another has a very public nervous breakdown, and problems at home don't just simply disappear.
Right now, the UK, along with France, is trying to build an international coalition to help reopen the Strait of Hormuz again, with about 40 other countries. There is a Nato summit soon, where defence spending will be an issue, as well as an EU summit, where the UK wants a closer relationship with the European bloc.
Meanwhile, the government's domestic in-tray is overflowing, and some decisions are already overdue. A defence spending plan, delayed for months, is sitting unsigned on the PM's desk. A consultation on tightening children's social media rules is about to close. Millions of households are waiting to find out whether they'll get help with energy bills ahead of expected price rises, and a promised review of fuel duty has yet to produce an answer.
Also pressing are calls to act on public sector pay, AI regulation, youth employment, business energy costs, mental health provision, migration, special educational needs and NHS staffing.
And that list doesn't even touch the biggest structural challenges: social care for the elderly, and a welfare reform programme that remains, for now, a promise without a bill. Those are all areas where decisions are due to be made in the coming months - even when the leadership is uncertain, government doesn't stop.
After the past few crazy days, does the prime minister have the authority to act? One cabinet minister tells me that for as long as Starmer is in the building, the PM needs to crack on: "We may have a way to go on this, so the focus in cabinet has to be on the job."
But is that possible? Truly? Labour MPs don't think that Starmer is going to be the boss for very much longer, so his ability to persuade them to back anything controversial is tightly limited. Cabinet ministers no longer depend on his favour for their futures either.
One of the reasons he's being pushed towards the exit is not just because of that old bogey man "comms" - his trouble with telling the public a convincing story. Nor indeed is it because his authority is draining away. But it's down to something more basic - his inability to make decisions with strong political instincts of what he wants to do. As one minister who had backed him told me: "Where we've gone wrong is lacking a clarity of conviction and belief in our project," suggesting the PM's biggest problem has been struggling with "making good quality decisions at speed".
They would all despise the comparisons, but Theresa May, Boris Johnson and Keir Starmer all have something in common - all their teams used to despair at the time and pain it took them to make up their minds. May was always said to ask for more information rather than decide, and Johnson was nicknamed the "trolley" because he changed his view so often.
And Starmer? His colleagues have struggled so often to know what he really wants that even one of his allies joked that his way of operating is to arrive at the right decision in the slowest and most painful way possible. No-one needs point out to Starmer himself that changing the leadership mid-government causes huge disruption to Whitehall and the country by slowing down the government's work and peeving the public. He knows all too well because it was part of his script in opposition.
But there is one big decision that looms over all - will Starmer wave goodbye to Downing Street before a contest officially arrives, or will he try to stay and fight if it happens? With swathes of his MPs, many of his ministers, and the groups that pay Labour's bills, the unions, on the record saying he can't be the man to fight the next election, it would appear standing in a race would be a choice to punch himself publicly in the face. This would be a near-certain embarrassment for a man who achieved something incredible - taking Labour from near oblivion back into power in four years.
Downing Street's official position through these crazy days has been that Starmer would run, but as a shadow contest gets under way, it's hard to know if that will hold.
This weekend, even some of those I've talked to, who know him well, find it hard to read. There is a sense in No 10 after the frenzy of this week that there's time now to figure out what to do. As one source said: "Now we are out of the constant live fire, we can do some thinking about what to do."
Starmer was in front of the cameras on Friday, visiting a police station before the planned protests this weekend, but not in front of microphones. We don't expect to see or hear from him this weekend, whereas Burnham and Streeting are both likely to pop up.
Burnham and Streeting have, with huge fanfare, made their decisions. But whether it's vital decisions in government or his own future, Starmer still has to choose.
Top picture credit: PA
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