This could be the crisis that spells the end of Gordon Brown's premiership and, perhaps, even propels an early election. Ever since Sir Thomas Legg carried out his urgent report, the rumblings of MPs have grown louder throughout the day at the expense of their leaders. Parties in crisis have set up meetings: the Parliamentary Labour Party met Harriet Harman and the 1922 Committee.
Such conduct as this called the word unedifying into being. No neologism is required. Early in the day, Cameron proclaimed that all Tory MPs would enter 'Legg before whip' or stand down at the next election. Brown, servant to the master of this manoevre, followed suit with a promise that his MPs would lose the whip if they failed to pay up.
Both leaders have forgotten that the ties of party only matter with the fear of the whip and the bribe of advancement. All that is lost. Why do they need to obey Brown or Cameron when the incumbency is up? This realisation may spread further and faster than the whips can respond:
The Prime Minister's own MPs began openly defying his call to pay back expenses claims, while some Cabinet ministers blamed him privately for allowing Sir Thomas Legg's investigation to run out of control.
They accused Mr Brown of enabling Sir Thomas to decide his own remit which has led to hundreds of requests for retrospective expenses payments by MPs.
Now the revolt is co-ordinated, shared and determined. Brown and Cameron have managed to achieve a bipartisan consensus of the mediocre and the entitled. Of course, these backbenchers, allied in indignation, must realise that the more they cry out, the more marked they are for decapitation by the electorate.
This is a useful fillip for the smaller parties and, ironically, indignant backbenchers, freed from the whip, may become a Parliament of individuals, for a while.