Why a Tory attempt to topple Boris Johnson is a case of ‘when not if’ and how it is likely to happen

Just two years ago, Boris Johnson led the Conservatives to an astonishing general election triumph, his personal popularity the decisive factor in demolishing Labour in its ‘Red Wall’ heartlands.

Yet the prime minister is now fighting for his political life, after a disastrous month that has seen public support collapse over allegations of sleaze and lockdown-busting No 10 parties – then Tory MPs desert him over his Covid strategy.

Some Tories now believe a leadership challenge is now a matter of “when not if”, so what happens next?

* How can Mr Johnson’s opponents get rid of him?

Not easily. Forget talk of a “stalking horse” candidate mounting a challenge, party rules allow only a vote of no confidence in a leader – which requires the support of 15 per cent of Conservative MPs, meaning 55 must submit letters to backbench steward Graham Brady. If the leader wins a subsequent vote, he or she can carry on, as Theresa May did.

* Is there a plot to gather those 55 letters and how many MPs have joined it?

Not yet, it appears. No Tory has admitted sending in a letter and MPs bang at the top of anyone’s list of likely plotters say they have not been asked to do so. Only Sir Graham knows if his drawer is filling up – and he has vowed to keep silent until the magic figure of 55 is reached. So any claims about the number of letters submitted are almost certainly guesswork.

* So the prime minister doesn’t need to be worried?

Oh yes he does....support is crumbling quickly and his opponents are merely “lying in wait”, until the best opportunity to strike, The Independent was told. “It’s a matter of when, not if,” said one, “but the timing needs to be absolutely right” – pointing out that Theresa May ignored more than 100 MPs demanding that she quit and simply staggered on.

* Who are the likely plotters when the New Year dawns?

Take your pick from a smorgasbord of One Nation ex-ministers who are terrified that Mr Johnson is – like Donald Trump and the Republicans – wrecking the party’s brand, “freedom loving” Tories who feel betrayed by his shift to supporting Covid restrictions and “newbies” who owe their marginal seats to him, but now see their postbags filling up with angry letters about government incompetence and fear for their jobs.

* So what are they waiting for?

Defeat in the (once?) rock-solid seat of North Shropshire, in Thursday’s by-election, would be a tipping point for some, but the Christmas break will then intervene. Paradoxically, the omicron crisis also helps Mr Johnson – because plotting looks unseemly, and no potential successor wants to take over, during such an emergency. But further dependence on Labour to force through Covid curbs will fuel the revolt. The crucial unknown is whether the factions will work together, which may depend on whether libertarian Tories – unlike the One Nation group – believe the prime minister is not yet a lost cause?

* What can No 10 do to keep Mr Johnson in his job?

The festive break allows for a “relaunch” – perhaps by bringing in a heavy-hitter to bring order to a chaotic Downing Street – but Mr Johnson has tried that trick before and many MPs believe he is simply incapable of change. A further worry is that the 2019 intake, in theory the most loyal, appears out of No 10’s control. One government aide blames the distraction of the pandemic for the MPs being “unwhippable”, saying: “It’s like a new puppy – if you don’t train them at the start, it’s too late.”

* Who will take over if the prime minister is toppled?

The chancellor Rishi Sunak and Liz Truss, the foreign secretary, are the favourites and have all-but started campaigning – the latter sitting on a tank, in a shameless Margaret Thatcher impersonation. Many Tories are terrified of life under the maverick Ms Truss, the favourite of the right-wing grassroots, and would probably seek refuge in Mr Sunak’s perceived safer hands.

* Then the political frenzy will calm down a bit, I imagine?

Well....in bad news for Brenda from Bristol, any successor will be strongly tempted to call a honeymoon election, before the economic pain from Brexit and Covid really starts to bite.