Are we there yet? Are we at the end of the Boris Johnson odyssey? It’s an impatient question, given it was only two years ago this very weekend that Johnson was celebrating a victory that brought an 80-seat majority and excited talk of a 10-year reign in No 10. An impatient question but one hardly confined to excitable Westminster journalists. The prime minister’s own colleagues are asking it of each other and themselves, prompted by the serial revelations of a torrid week. “Cummings was bad, but this is off the scale,” one minister tells me, reflecting the widely shared view that Dominic Cummings’ lockdown jaunt to Barnard Castle has been outdone by the video of sniggering Johnson aides implicitly admitting that they had been partying in Downing Street while the rest of the country faced a bleak, often lonely Christmas; that they had been knocking back the booze while many were denied the right to give so much as a consoling touch to a dying loved one. That imagery should be devastating for Johnson, who ran, however improbably, as the populist tribune of the people against the hated establishment. The mock press conference footage exposed that fraud. It confirms voters’ worst fears, says that same minister, “that the government is a conspiracy of elites, taking the public for fools”. Add to that the striking allegation that the PM misled his own standards adviser, Lord Geidt, over the source of funds for his absurdly extravagant makeover of the Downing Street flat – decorating Versailles while outside the palace the people trembled in the face of plague – and you have a prime minister confirmed as the embodiment of the very elite he claimed to oppose: pampered, greedy and out of touch. The result is that the man who united shire Tories with “red wall” Brexit voters to forge a winning coalition in December 2019 has crafted a new alliance in December 2021. He has brought together previously warring factions of his own party – the anti-mask crowd, good-government types who remember integrity, and the 2019 intake still waiting for Johnson to deliver on his promises – in unison against him. The latter group is the one watched most closely. There are a lot of them and they face constituents who made clear two years ago that they were merely lending their vote to the Tories, that their support was conditional. “When they are complaining,” says one MP of the class of 2019, “then he’s in real trouble. And they are.” All of this would obviously have finished off any normal politician, but Johnson does not fit that description. He has already survived so much – not just successive waves of scandal but a record of incompetence in the early handling of Covid that led to tens of thousands of needless deaths – that it’s tempting to reach the same conclusion that Johnson drew about himself long ago: to him the normal rules do not apply. You can imagine him staggering on until the Christmas cessation of hostilities, then returning in the new year full of new promises and new slogans, breezily dismissing the current agonies as old news. Such are the arguments of the Westminster village, as cheerleaders and critics trade competing scenarios. But there’s one player missing from these dramas, in which all power rests with the 361 members of the parliamentary Conservative party. That missing player is the electorate. So often our politics is like that, the public reduced to a data point, their involvement limited to one say every four or five years and the muffled voice they are granted in the form of digits on an opinion poll. Happily, next week may be different. There is a byelection in rock-solid North Shropshire, the seat vacated by Owen Paterson, the man who broke lobbying rules, and whom Johnson wanted to let off without punishment. Given that Tory MPs’ attachment to Johnson is deeply transactional, contingent solely on his electoral prowess, a shock result on Thursday could prove to be a tipping point. Defeat there will spark mass panic among Conservative MPs: if that seat can fall, they will say to themselves, then what about mine? Even Labour’s most optimistic souls concede they cannot win North Shropshire, which leaves the Liberal Democrats as de-facto challenger. But some Labour tribalists are hardly enthused by the prospect of a Tory defeat there at the hands of the Lib Dems. They worry a revived Lib Dem party could be a headache, and they’d prefer to see a weakened Johnson remain in post. One senior Labour figure says “it’s a no-brainer” that the party should not want to see the Tories repeat their trick of 1990 and 2019 – switching leaders, so the public feels it has had the catharsis of a change of government without changing the governing party. Much better, runs the argument, for Johnson to limp on to the next election, where he’ll be a scandal-plagued, damaged-goods PM facing former prosecutor and straight-arrow Keir Starmer. That, they say, is a contest Labour could win. I get all that logic. But politics can’t always be about gaming out scenarios and plotting chess moves. Sometimes it’s simpler than that. In this case, the plea needs to go out to the Tory voters of North Shropshire. They were cheated by their Tory MP, who promised to work for them but was found to be lobbying for the companies that paid him handsomely. They have been cheated by a Tory prime minister who has lied and lied – setting the rules for everyone else while he and his chums broke them without a second thought, laughing at the saps who were stupid enough to comply. This isn’t only an offence against the integrity of our public life, it’s a danger to our public health. Because you cannot fight a pandemic if the government’s instructions will no longer be followed. Many Britons will look at Cummings’ eye test and the Secret Santa in No 10 and decide they won’t be fooled again. We face a government that is cruel, useless and rotten from the head down. The voters of North Shropshire have a rare chance on Thursday to declare that the citizens of this country will not just take it. That they won’t just shrug and say, “That’s Boris.” That they will demand better. The political after-effects will take care of themselves. The most immediate task is to send Downing Street the clearest possible message: the party’s over. Jonathan Freedland is a Guardian columnist