@Walter Hinteler,
The collapse has been sudden. Johnson was already in the last chance saloon before Pincher's arse grabbing came to light.
It's the obvious lying, and getting ministers to lie on his behalf that did it.
Politicians don't usually deliberately lie, they evade the question, they twist and spin things to their advantage, and they run to certain narrow, or wide, interpretations.
Johnson lied, he did what he always does chooses the expeditious option, and not the right one.
He was caught out by a civil servant going on record with the truth, after getting ministers and press officers to lie on his behalf he had to admit his culpability.
I read that he was never popular with the bulk of the party, that when he became party leader there was a sense of having dealt with the Devil. Normally the leader would reach out to his MPs, but after winning such a huge majority he didn't bother.
Those who reluctantly voted for him didn't bank on this level of incompetence, the amount of unforced errors has been astounding. Every day there's another revelation or an admission. It's a farce.