One point that occurs to me is that it's been clear for some time that Chaytor et al were personae non grata. Why therefore has Chaytor been used as a government plant at PMQs twice this year? The MPs’ expenses scandal is the one Village obsession that resonates with the public; Brown’s judgement on the whole issue has been staggeringly naive.
PS: Brown beginning to get his act together - Laura Kuenssberg reports that a spokesman has not ruled out a change in the law on parliamentary privilege if Chaytor et al declare themselves immune. The day is already Cameron's, who called for such an act this morning, though I still think he'd be advised to calm his ad hominem tone in the long-run - of course Brown is of Westminster's ancien regime, don't throw away the advantage with the 'bad old politics'.