The 1st stage is 15% of Tory MPs have to write to the 1922 committee wanting him out.
Then there is a vote and 50% of Tory MPs need to vote to ditch him ( if Johnson wins he is immune from being deposed for a year ).
Then there is a leadership contest.
On my reckoning, 15% is about 54 MPs. Would Johnson be as ruthless as he was to anti-Brexit Tories and just remove the whip from them? That would still give him a good majority of 24 but he’d have complete control of the Parliamentary Party. They’d think twice about sticking their heads above the parapet again.
Despite the highly orchestrated ‘bumbling’ character, Johnson takes his career extremely seriously and would throw anyone under the bus to achieve his aim of staying in number 10, even relatives from one of his own families.
Johnson WAS an absolute weapon in elections but too many people see him for what he is now, he is the worst of politicians, undeniably self serving to his core.