Cameron
Today he was having a go at Brown for being soft on expenses or doing u-turns or something. There really is no mileage in this. Voters regard all parties equally to blame and equally guilty. The voters will not buy into an idea that the Tories are better than Labour on expenses, although because Labour is in power, it has de facto more to defend. This is useful to the Tories but to raise a campaign issue of it makes Cameron look rather tacky. This is what you call a silent advantage; make a noise and it plays against you.
The Tory High Command, beginning to look ever more mud splattered and out of its depth, needs to understand that the public pay little account of the fact that the money is being paid back. As far as voters are concerned when MPs of all parties had the opportunity to get their hands in the till unseen, they took the cash. They remember also that the outlandish moats and duck houses were Tory must haves at public expense. Oh and that wisteria too.