Apparently MPs knew this was coming down the pike for a good few years. If I was a third party who, in the public's eyes and apparently also in their own, don't stand a chance of getting into power I might have had the foresight to do the honourable thing and not claimed expenses en masse. Then when the two main parties impaled themselves on this issue I'd have made damn sure that being unimpeachable we'd have ridden this all the way to the next election. Jon Snow posts on his blog that:

"According to one of my well-informed sources, David Cameron’s greatest fear about this continuing crisis is that a credible group of people will come forward and form some sort of party that will contest the next election on the basis of campaigning for one term only, to clear out the current sleaze, institute wholesale parliamentary reform, and then leave the field."

A credible group of people... the Lib Dems should be kicking themselves that this group isn't them.  Nick Clegg's defence of Andrew George looked pretty weak as well it might from someone who was rinsing the system as much as possible.