Boris Johnson flew back to London from India on Friday, probably wishing he could stay longer in a country where he was greeted by dancers, avenues lined with children waving union jack flags and billboards featuring his ruffled features.

“I felt like Sachin Tendulkar,” the UK prime minister said, referring to the Indian cricketing demigod. But away from the temples and the trade visits, Johnson spent much of his trip to India gazing over his shoulder at the political peril unfolding at home.

By Thursday afternoon, Johnson was facing questions about the new Conservative rebellion at Westminster, sweat trickling down his face in a series of television interviews at a temple in Gujarat in 40C heat as the scale of the shambles became clear.

Margaret Thatcher learned in 1990 the peril of being abroad when a party revolt is in full swing. Johnson could do little but watch as he lost control of his own MPs, with many no longer prepared to back him over the “partygate” affair.

One close ally of the prime minister in London said: “He should have been here, working the tea rooms and trying to reassure colleagues. Instead people have just seen clips of him looking exasperated.”

By the time he closed his two-day visit in New Delhi on Friday, a frustrated Johnson did not want to talk about the Covid lockdown parties, preferring to answer questions about them from journalists by talking about wind farm collaborations with India.

But the situation for Johnson is grave. On Thursday, it became clear that his party managers at Westminster did not understand the worsening mood among Tory MPs, let alone know how to control them.

“I had a feeling in my bones something was going to go wrong,” admitted one member of Johnson’s team in India, the moment Chris Heaton-Harris, Conservative chief whip, backed the idea on Wednesday night of asking Tory MPs to kick the issue down the road again.

Heaton-Harris, brought in to restore party discipline in February, told Johnson that Tory MPs would back a wrecking amendment to delay for weeks the Labour party’s attempt to instigate an inquiry into whether he had deliberately misled parliament over partygate.

During the course of Thursday Heaton-Harris realised he had a full scale revolt on his hands, with the possibility of ministerial resignations and the equally worrying prospect of Conservative MPs simply heading home rather than backing the prime minister.

Johnson, on a visit to a JCB factory in Gujarat, was told of the worsening mood and agreed to simply accept the inevitable. “There were some questions over the whipping,” said one cabinet member, with studied understatement. Johnson was furious.

“So much for the new efficient operation,” said one former cabinet minister. “The whips didn’t check with people whether they would accept the amendment so they only found out there would be a big abstention after they laid it. So they backed down. Shambles.”

The result was that the Commons privileges committee now joins the Metropolitan Police and the senior civil servant Sue Gray in conducting inquiries into the parties affair.

The fact that Heaton-Harris, widely liked among Tory MPs and trusted by Johnson, misread his party so badly takes the partygate saga into a dangerous new phase: Number 10 cannot be sure exactly what his MPs will do next.

Johnson hopes his “business as usual” approach and robust stance on Ukraine will put a protective ring around him and that there will never be a critical tipping point at which at least 54 MPs — the number needed to trigger a confidence vote — mobilise against him.

But Conservative MPs are wearying of the apparently never-ending and corrosive saga. On Tuesday, worryingly for the prime minister, few MPs stayed in the Commons to back their leader as he made a statement on the issue.

The bad news is likely to accumulate in the coming weeks, with the possibility the prime minister receives more police fines, the publication of Gray’s report, which is expected to lacerate the culture inside Number 10, and local elections on May 5.

That date is being seen as a moment of reckoning for some Tory MPs. Even some MPs who have privately backed Johnson until now believe the game is up and that he is on borrowed time.

One Conservative backbencher, previously supportive of Johnson, said: “We are now in a realm where we have to support a lawbreaker. And because of that he has got to go.”

Tobias Ellwood, chair of the Commons defence committee and a critic of Johnson, told the BBC: “It’s now when, not if, a vote of confidence takes place”.

One former cabinet minister said there was a “considerable swell of support” for Jeremy Hunt, former foreign secretary, to replace Johnson once the May elections are over, although the prime minister benefits from the fact there is no clear alternative waiting to replace him.

Steve Baker, the former minister who turned against the prime minister on Thursday, told the Commons he was incensed by Johnson’s demeanour at a private event of MPs earlier in the week, where instead of apologising he sounded bullish.

Another MP at the private event said: “In public he may have been all contrite and apologetic, but behind closed doors it’s clear he still doesn’t get it.”

Ministers are also tiring of having to compromise their own reputation by defending Johnson. “Every time you go on TV, this is all you’re asked about,” said one. “It feels like it’s never going to end.”

But cabinet loyalists insisted that in the end the party will pull back from the brink. “The truth is it’s not terminal and the PM will bounce back as long as there aren’t more significant events to come,” one minister said. But after the events of this week, nobody can be certain what will come next.