Westminster Abuse Allegations: Why Now?

I'm confused. Why has the Westminster abuse scandal erupted now? Given that most of the allegations and the culture in Parliament were common knowledge and historical in nature, what is significant about the timing? Why Now?

Sure, Guido Fawkes has pushed the agenda against certain MPs, but the size of the issue tells me that there is something else going on. Like a Magician's audience, we're being distracted, but what from?