The vultures are circling again, just two years after the Conservative party tore apart its last leader. Here is yet another “worst week” for the beleaguered prime minister, after his planned week announcing new crime policies switched to probes into possible Downing Street law-breaking. When getting “rat-arsed” at Tory parties becomes this year’s topical panto joke, things have turned serious. He faces a major rebellion on Tuesday, his Covid regulations likely to be saved only by Labour’s public health seriousness. The following day he faces another pasting at prime minister’s questions and on Thursday a byelection. With Labour nine points ahead nationally, North Shropshire may be held and yet still signal such a Tory collapse that statistically it endangers Boris Johnson’s own seat. Voters knowingly elected a liar, but they rarely forgive chaotic incompetence. Johnson’s fate rests with those who elevated him, the nexus of parties-within-a-party that hold the real Tory power. This week Steve Baker MP relaunches Conservative Way Forward, founded to guard Margaret Thatcher’s flame. These idolaters ask themselves “What would Maggie do?” with as little historical sense as those who claim to know the answer to “What would Jesus do?” A prime saboteur, Baker is an agent in all the rightwing caucuses that riddle the Tory party. He chairs the Covid Recovery Group, which is stirring the plan B rebellion; he is a core member of the European Research Group (ERG); a member of the Global Warming Policy Foundation, a group of deniers blocking climate-saving action; and founder of the Cobden Centre, promoting hardline free-market economics. As a sky-diving, born-again Christian who was baptised in the sea, Baker also belongs to the Cornerstone group for family, faith and flag, and voted against same-sex marriage. All revolutionary insurgents need new causes. Baker’s airy manifesto for the Way Forward in the Sunday Telegraph declares “the Conservative party is in the wrong place”, accusing it of “carrying on with centre-left policies”. In a litany of objections to Covid regulations, he protests: “Conservatives don’t create societies where people must live and work in fear a minister might, without notice, impose restrictions on them.” As Omicron arrives in over-filled hospitals, he says Johnson’s plan B is “creating a miserable dystopia”. Yet for all his low-tax yearning, Baker has just enough political sense never to say what public spending he would axe. Prof Tim Bale, a political party analyst, points to the reason: two-fifths of Tory members are over 65, cleaving to state-financed social care and the NHS. Johnson’s enemies, the remainer greybeards he threw out, such as Ken Clarke, Michael Heseltine and Dominic Grieve, may smile at the irony of seeing him now threatened by turbulent disrupters. This new cadre model themselves on the Trumpian Republicans of the Christian right. “I believe God means us to live in liberty,” Baker told the Financial Times. Does that stuff fly in North Shropshire? Johnson would be in less trouble if his government was charging full-speed ahead in any direction. Instead, he dithers between levelling-up and small state austerity, zigzagging between slogans without policies, while laced into an eye-watering budgetary corset. Without fast-forward propulsion, governments topple. With gracious condescension, Baker says he’s not seeking Johnson’s head on a plate, yet: “I want Boris Johnson to rescue his position,” he says. “Things are not good.” If they tire of Johnson, Liz Truss is the obvious candidate to be his successor. Her brazen zealotry frightens many: Dominic Cummings calls her a “human hand grenade”. A founder of the Free Enterprise Group and co-author of the notorious new Tory right manual Britannia Unchained, her photo-ops mimic Thatcher imagery – in a tank, hugging a calf – yet she lacks her idol’s political filters. Who else would try solving the childcare crisis by deregulating childminders to let them each take in six two-year-olds? Conservative Way Forward is founded in a belief that the party is no longer recognisably conservative: if so, they are the entryists who subverted it over decades. Where Neil Kinnock rooted out the Militant tendency tearing at Labour’s grassroots, the Tory party has always appeased its rebels. When Baker was chair of the ERG, Theresa May made him a minister. When Suella Braverman took over as ERG chair, she was similarly rewarded. Even her ERG successor, the outlandish Jacob Rees-Mogg, was swept up into government. The deputy ERG chair, Andrea Jenkyns, has been elevated to the whips’ office, a bizarre appointment given the ERG’s own hostile whipping operation. Through failing to stand up for the conservatism of Harold Macmillan and Edward Heath, the Tory party has plunged further right than most of its voters. Just 200,000 largely rightist party members have for several decades selected none but Brexiters, libertarians and obsessive state-shrinkers. The result, according to Bale, is that the MPs they picked are now even further right than those party members. About 100 Tory MPs may vote against plan B, well beyond the usual suspects, including relative moderates such as Tom Tugendhat and Tobias Ellwood. Some MPs feel pressure from local parties, while others are simply venting fury at Johnson’s catalogue of failings. But remember this: those who vote against measures to tackle Omicron are irrationalists defying the best scientific opinion. Sir Graham Brady, the head of the 1922 Committee, calls these modest restrictions “Soviet-style”: reaching for Stalin really is the end of rational debate. Here is a party falling apart, eaten from within by failure to extirpate extremists. This is not primarily about Johnson’s unfitness for office. It’s about the bizarre and dangerous nature of the extreme party that put him in power and will replace him, as the whim takes it. This is about a party that has become unfit to govern. Polly Toynbee is a Guardian columnist