Editor's Note: (Rosa Prince is editor of The House magazine. She is the former assistant political editor of The Daily Telegraph and author of the books "Theresa May: The Enigmatic Prime Minister" "and "Comrade Corbyn: A Very Unlikely Coup." The views expressed in this commentary are her own. View more opinion on CNN.)
(CNN) The moment Boris Johnson realized his premiership was in jeopardy came not at 9 p.m. Monday in the House of Commons when Sir Graham Brady, chair of the 1922 Committee of backbench Conservative members of Parliament, announced a painfully narrow victory in the no-confidence vote, but three days earlier on the steps of St. Paul's Cathedral.
Johnson clambered out of his chauffeur-driven car, wife Carrie at his side, to attend a service of thanksgiving for Queen Elizabeth II's 70 years on the throne; a murmur rose from the waiting crowd, a low grumble that rapidly coalesced into distinct boos.
It is not uncommon for senior politicians in the UK to be jeered in public, but boos from this assembly of monarchists and traditionalists who had turned out on a windy bank holiday to celebrate an absent monarch and were overwhelmingly likely to have voted Conservative at the last election must have jolted Johnson to his core.
In the past, his gleeful insouciance and glorious erudition had earned him something like a political hall pass, permission to shrug off a myriad of transgressions, both personal and political, any one of which would likely have torpedoed less blessed politicians.
But with that genteel heckling at St. Paul's Cathedral, something became apparent to him and everyone who heard it: This was the moment it was clear the British public had finally fallen out of love with their Prime Minister.
The disappointing margin of victory in the vote of his party's members of Parliament on Monday night only compounded a truth he had already absorbed days earlier.
During a week away from Westminster for the parliamentary recess that included the Queen's Platinum Jubilee celebrations, Conservatives had taken the temperature of their constituents and confirmed their suspicions. Johnson had lost his Midas touch.
The booing confirmed their worst fears, and the vote that followed once the Jubilee celebrations were over and they were back in Westminster became a rejection by colleagues who saw little point in keeping Johnson in power if he had lost his magic trick of wooing voters other Conservatives couldn't reach.
Because the problem with being a populist is that when you let your people down, the betrayal is a highly personal one.
More perhaps than any politician before him, Johnson -- "Boris," as, tellingly, voters invariably referred to him no matter their view of him -- was sustained in power thanks to his personality, not his policies.
While his supporters did their best to hype him as the man who saw Brexit across the line, it was difficult to forget that as foreign secretary he famously wrote two opinion pieces for and against departing the European Union before plumping for Leave, seemingly, his critics insist, on a whim.
No ideologue, he won power as, more or less, a social libertarian, low tax Conservative, mainly because it was expedient to do so. Once in office he presided over the biggest increase in personal taxation in decades, confined tens of millions to their homes for months and introduced a proposal to deport illegal migrants to Rwanda, again not because he particularly believed in his bones in the righteousness of such schemes but because that seemed to be the directions the winds were blowing.
But it wasn't the flip-flopping on policy that led Britons to cast Johnson out of their hearts: It was something far more personal.
On the surface, the scandal involving the Downing Street parties during lockdown that were found to have been in breach of the coronavirus regulations appears a trivial affair compared with the serious issues facing the UK: the cost of living, war in Ukraine, the challenge of ending inequality.
But when each and every voter can remember their sacrifices during that strange, intense and fearful period, the saga became intimate, personal. Many were utterly appalled that at the center of power, far from being "in it together," as voters were assured, those making the rules were flagrantly breaking them. While Downing Street partied, ordinary Britons remember, they missed funerals, struggled to home-school their children, lost jobs.
It made them angry at Johnson in a far more visceral way than the disappointment they might have felt when he jettisoned a policy or made a U-turn on a decision. Thinking of him as a friend, even a family member, they felt let down by him, in the way one might a friend or lover who fails us.
When Margaret Thatcher survived a no-confidence vote in 1989, a year before she was eventually toppled, she was advised by her MPs she would be safe if she ditched her hated poll tax and took a more collegiate approach to the team around her.
A generation on, and in 2018, having scraped through a vote of her own, Theresa May was counseled that she would be safe if she stopped the chaos surrounding the Brexit process and led Britain safely out of the EU.
Neither woman was willing, or, perhaps more accurately, able to take the advice, and both were out of office within 12 months.
And what message have Tory MPs sent Johnson with this latest vote: What can he do to revive his premiership? What policies should he change? What adjustments could he make?
None. Because when the problem is not your ideas but your character, and it is a character the public no longer trusts, then there's nothing you can do.
Johnson has survived the vote -- for now. But the message from the crowds outside St. Paul's has come through loud and clear -- the party is over, and they're ready to move on.