Does it matter? Probably not, because if Boris Johnson wasn't such 'a character', he probably wouldn't have been elected to be Mayor of London in the first place.
Meanwhile, it's got me wondering whether I've seen any comparable 'characters' since I started taping and observing party conferencs 30 years ago.
So far, the best I've been able to come up so far are only 'possible' candidates, as they're not really in the same league on the comedy front: Rhodes Boyson (Conservative), Dennis Skinner (Labour) and Cyril Smith (Liberal).
I'd be fascinated to hear of any other nominations you might have.