It was a minute or so into his BBC interview on Friday morning, after being asked about “moves” to remove Keir Starmer, that Steve Reed ran out of patience. “There is no contest,” he interrupted. “‘Moves’ mean nothing. People need 81 nominations to stand against the prime minister.”

The housing secretary, a close ally of Starmer and a founding member of the Labour Together thinktank that catapulted him to power, was right, of course: no one has formally challenged the prime minister, let alone ousted him.

But the reality is stark. In one short but tumultuous week, Starmer has shed so much authority that many of his MPs – let alone the wider public – view him as, in effect, an interim leader, still in office only until the necessary arrangements can be made for a replacement.

This risks being an oversimplification. After Wes Streeting resigned as health secretary but seemingly edged away from a leadership challenge, Andy Burnham is seen as the successor apparent. But the Greater Manchester mayor is not yet in parliament and will first have to win a byelection in Makerfield, a constituency on the edge of Wigan where Reform UK is bullish about its chances and where the Greens are also likely to campaign hard.

Those around the prime minister insist that not only will he fight on but that it has been utterly bizarre for a party that spent much of its time in opposition on internal battles to do the same less than two years after a landslide election win.

“At several points this week I’ve felt like I was going mad,” said one Labour official loyal to Starmer. “Why are we even doing this? You can’t go around saying ‘the PM has to leave, and we don’t know who will replace him’. It’s wildly irresponsible.”

That was, however, more or less how the week’s events began. On Saturday, two days after Labour received a drubbing in elections across England, Scotland and Wales, one of Starmer’s lesser-known MPs did her best to light the spark on a contest. If this was one of the more unpredictable weeks in recent UK political history, Catherine West was its mascot.

She began by saying that if no one in the cabinet was willing to seek the 81 nominations needed to kickstart a leadership race, she would. This became an email to Labour colleagues asking Starmer to step down.

Eccentric it may have been, but it heralded three days of what could be termed the phoney war to get rid of Starmer, as the various camps marshalled their forces and began some exploratory skirmishes.

On Monday a handful of junior frontbenchers, mainly allied to Streeting, quit government. That evening, several cabinet ministers asked the PM to think about a departure timetable.

By Tuesday the resignations had been upgraded to junior ministers, most notably Jess Phillips. Again, these were primarily from Team Streeting, although the first, Miatta Fahnbulleh, said she was quitting to press No 10 to allow Burnham back into parliament.

Wednesday saw an intense effort by Downing Street to essentially dare Streeting into a formal challenge. Starmer agreed to see his then health secretary for a humiliatingly short meeting, while the PM’s allies briefed furiously that Streeting had nowhere near the 81 MPs needed and had “bottled it”.

It took until Thursday for events to start coming into focus. At lunchtime, Streeting released a long and damning letter of resignation from the cabinet, calling for a leadership contest with a “broad” field of candidates, a de facto acknowledgment that he lacked the MP numbers. In one of the most bizarre turns of the wheel, this was also the day that West told the BBC that if a contest did happen, she might support Starmer anyway.

About four hours after Streeting resigned, when just about every other Labour MP in the north-west of England had denied they would stand down in Burnham’s favour, one did. Josh Simons, a 2024-intake Labour MP, has roots more on the centre-right of the party but has yoked his fortunes closely to the Greater Manchester mayor.

As chance would have it, Reed was on stage at an event when this news emerged, with footage showing his brow furrowing as he was informed by a politely gleeful Michael Gove.

A couple of hours later came what appeared to be the final piece of the puzzle: Downing Street indicated that the party’s national executive committee, which had blocked Burnham from standing in February’s Gorton and Denton byelection, would not do the same this time.

For Burnham supporters, the way ahead seemed clear. Their man would be selected for the seat, use a strong personal brand built during nearly a decade as mayor to overcome Reform, and be back in the Commons. The idea, some allies said, would be to immediately challenge Starmer and be in No 10 before the Commons went into summer recess in July.

It is a bold plan but one with several obvious hurdles. If Burnham loses the byelection to Reform, his ambitions would seem at an end, his supposed superpower – “only I can stop Nigel Farage becoming prime minister” – shattered. For good measure, his departure as mayor has the potential to deliver Greater Manchester to Reform as well.

Even getting into parliament might not be the end of it. For all that it may at times be based on a mix of braggadocio, desperation and narked fury, Starmer’s allies continue to insist that he would contest any challenge and call on the Labour membership, who make the final decision, to stick with stability.

Such an approach does thus far appear to have seen off Streeting. It is difficult to understate how much this has been a source of comfort to Starmer’s supporters in an otherwise painful week.

“This was Wes’s moment and he messed it up,” one said. “Everyone has been expecting him to go for it more or less since we got into office, and this was his chance. And he got 40 MPs. It’s embarrassing.”

Things remain hugely tricky for the PM despite marathon efforts by allies including Darren Jones, the minister who serves as chief secretary to the prime minister, who spent six hours on Wednesday evening trying to talk MPs down.

Starmer faces very obvious constraints, not least the fact that, as shown by a generally pedestrian “make or break” speech on Monday, he remains a poor communicator with few clearly articulated ideas who is widely disliked by voters.

There are some signs of greater boldness – for example, comments on Friday condemning a far-right march planned for London the next day as part of “a fight for the soul of this country”. Similarly, No 10 insists voters are starting to see results, with the chaotic week burying news of a big fall in NHS England waiting lists and better than expected economic growth.

But even some allies in the cabinet accept that at some point he may have to face that the game is up.

“If you get to the point, closer to the election, where he can’t win the election but somebody else could, where he’s clear in his own mind that it can’t be done, then he’d make sure there was an orderly transition,” one said. “But he’s not there yet, and less than two years after winning a general election, nor should he be.”