The extraordinary resignation of Boris Johnson's deputy mayor Ray Lewis saw me called in to BBC London on Friday night to take part in a discussion on the Tessa Dunlop show that involved London Assembly members and callers from around the capital.

It was two hours of lively debate as we all tried to take stock of the fact that Johnson, elected just two months ago on 1 May, has already lost two key players in his set up - the other being adviser James McGrath.

There was genuine sorrow on the part of some callers who pondered just who could take on the job of tackling youth knife crime. Some blamed the media for asking questions - which is a tack that always astonishes me.

Strangely no-one from a Tory perspective wanted to come on the show. Must have been licking their wounds. You can listen to the debate by going to the BBC's listen again service