Dave:
It is a fact that Bozo is a liar. Do you want me to post the list of lies again? If that were not enough it is also a fact that there were gatherings at Downing Street which, even if they were within the letter of the law, were certainy against the spirit of it.

Allow me to split that down:
It is a fact that Bozo is a liar.
Is that consistently? Like one of the two men stood at doors to death or freedom, one of which always lies, one of which always tells the truth?

Do you want me to post the list of lies again?
No really. I've seen it before and it seems to be based on the idea that if you throw enough mud, some of it will stick.
Some of the claims in it may be deliberate lies, but as I recall some are statements of intent which were later overtaken by 'real life'. Some were statements of facts as he understood them at the time.

it is also a fact that there were gatherings at Downing Street which, even if they were within the letter of the law, were certainy against the spirit of it
Thank you for that acceptance. It is breaking the letter of the law which is illegal. Lawyers make a fortune arguing over the precise meaning of the written law, and it is the written law which can be enforced.

Apparently the 'ministerial code' requires Boris to resign if it is shown that he has deliberately misled Parliament. If this is so, and it can be shown that he has done this, then he should resign.
The election of a leader is then up to the Conservative Party. I would hope that Boris gets proposed for the post.
He may appear a buffoon at times, he may mislead (either deliberately or otherwise) but he gets the job done.