I would take something appalling to emerge in his character to diminish my respect for Eddie Mair. Ever since this:
https://www.theguardian.com/politics/2013/mar/24/boris-johnson-interview-eddie-mair
Johnson went downhill at an alarming pace until by the interview's close, admitting he had "sandpapered" quotes as a Times journalist, failing to deny he lied to the party leader at the time, Michael Howard, about an extramarital affair and conceding that he had humoured an old friend when he asked for a phone number in the knowledge that the friend intended to beat up the owner of it.
By the interview's close, "You're a nasty piece of work, aren't you?" was one of Mair's more generous reflections on Johnson's integrity.
Sadly, it seemed to make zero difference to the adulation expressed by the Boris fans out there at the time, and now seems to be been simply absorbed in to the "Boris being Boris" explanation* for his history of self-serving shadiness and dubious effectiveness in any role whatsoever, personal or professional.
* It's unclear why people expect this to resolve the issue. As a colleague of mine once pointed out, if you heard someone say something disgustingly racist and challenged them on it, you would hardly be content with the explanation: "Well, I am a racist!" Would you?
Than again...