That's not entirely fair, akenaton. There been quite a lot of people outside the political parties calling for various reforms such as a written constitution, better separation of powers etc for a LONG time. For example, Charter 88. I would agree though that the number of members of groups like that is, quite literally, negligable as far as the career politicians are concerned.
It is the unity in the general public over this expenses scandal that has made the topic of reform hot. Even so I think our chances of getting a real reform rather than just publishing expenses is slim. For example, I have come up with a scheme where all expenses are published and 'reasonable', no pay rise is needed but the MPs could still milk the system for tens of thousands.
No, I'm not going to explain how to do it - they will manage it themselves!