Boris and the Routemaster

You can learn more about the new routemaster bus than you probably want to here. The argument is that the whole thing is a hugely expensive politically driven vanity project.  Had Ken Livingstone been responsible for such a profligate waste of money, the Evening Standard would have been gunning for him.  Yet, I haven't seen a similar reaction to Boris' extravagance, despite Boris making his supposed fiscal responsibility a core part of his pitch. Why?