From the Politics site:
Boris Johnson's encounter with an audience of teenagers yesterday was preceded by a "busk off". A talented bunch of young street musicians, the finalists in a competition forming part of the London mayor's Rhythm Of London music education campaign, did their stuff in a theatre side bar at the O2 in Greenwich. Each act was polished, poised and engaging. Apart from the last of these characteristics, their performances contrasted sharply with the mayor's.
The chaos of his hair shattered all previous records, by the way. Now read on.