Of the three main Party Leaders David Cameron has, in my opinion, responded the swiftest to the concerns of the electorate. While Nick Clegg has tried to respond, he has been hampered by the fact that his MPs seem to want to argue the toss and therefore his proposals/orders haven't had the same 'grab appeal'.
As for Gordon, he's still wondering what his MPs have done wrong & hasn't yet realised that the majority of voters are white-hot with anger. He has taken some action, in suspending Elliot Morley - the MP claiming for a non-existant mortgage - but even that took until lunchtime, by which time Tory Andrew MacKay was dust. He and his MP partner, Julie Kirkbride had claimed expenses in a manner not dissimilar to Labour Ministers Balls & Cooper.
Meanwhile, MPs seem to be banding together against the Speaker. He has not filled the role of Speaker well. He has spent taxpayers' money trying to keep MPs' expenses secret. Why? Has he something to hide?