Westminster’s expenses scandal goes from bad to worse – just when you thought it had hit rock bottom. There’s the latest revelations, this time involving Tory MPs and swimming pool repairs, moat clearing, chandeliers, and vast quantities of horse manure – though I would have thought that particular commodity was not in short supply at the moment.

Worse, however, has been the appalling attitude of the Speaker, who on Monday reacted with fury to probing and perfectly proper questions from the Labour MP Kate Hoey and myself. To be frank, there’s long been widespread unhappiness with Speaker Martin, right across the House, but MPs have naturally been reluctant to attack the Chair (and of course risk not being called to speak). But if the Speaker is going to take off his umpire’s hat and put on his player’s one to shut up MPs and attack them from the Chair, then he cannot in return be surprised if MPs attack him back.

Some of us have been campaigning for a reform to the expenses system for years, and the sad fact is that the greatest obstacle to progress has been the House of Commons Commission, the small body of senior MPs, chaired by the Speaker.

It is the Commission that blocked my very modest Freedom of Information request for a breakdown of MPs’ travel by mode, and spent over £20,000 of your money doing so. And when they lost, they engineered behind the scenes a shocking attempt to exempt MPs from FoI altogether, which a few of us had to filibuster in the House to derail.

All along, the Commission has only given ground when it absolutely had to, and has never really shown it understands or accepts the need for drastic change. I believe the time is now right for the entire membership of the Commission to be changed.

It doesn’t help that the torrent of revelations in the press has come at a time of recession, with people losing their jobs and fear of worse to come. And yet still many MPs, even now, fail to understand the need to face up to reality, to apply the emergency brakes as the reputation of Parliament hurtles ever faster downhill. And so we have MPs criticising the Telegraph for revealing details that were largely due for release anyway, MPs wanting to call in the police, as if shooting the messenger is somehow the answer to this mess, and the chutzpah of Peter Mandelson, attempting to spin that this is all some sort of smear campaign. In this case, his spin looks more like tailspin.

Worst of all, we have MPs plaintively insisting that whatever they have claimed has been “within the rules”, rules of course written by MPs themselves. That particular defence may give legal cover, but it is all too redolent of the “I was only obeying orders” type of excuse. What matters is not what the lax rules have permitted, but where an MP’s own moral compass points, and whether we can face our electors and defend our own use of taxpayers’ money. Many will struggle to do so.