Leading article: Parliament must put its house in order – and quickly

The scandal surrounding MPs' perks, in which Derek Conway emerged as the central villain in the pantomine, is not going away. On the contrary, there has been the drip-drip of unedifying disclosures about the way MPs abuse public money and their offices. Take the unsavoury revelations surrounding the housing allowance. As with so many of these privileges, the rationale behind the Additional Costs Allowance, or ACA, at first looks unarguable. Most MPs do not represent constituencies close to the House of Commons and so need an allowance to rent a flat in London or to pay the mortgage on a second home in the capital. But it is becoming clear that supposedly honourable members have routinely drawn the absolute maximum of £22,110 a year on ACA – a sum since increased – as if it were a supplement to their £60,000-plus annual pay.

Indeed, this stipend appears to have been diverted towards all sorts of purchases, ranging from new kitchens to iPods. MPs admit they use the money to pay for the mortgage on a third property, which they rent out and can sell upon retirement for a thumping profit. The latest miscreant to emerge is Michael Ancram – marquis, multimillionaire and owner of three properties worth about £8m – who claimed just £80 short of the maximum ACA last year in order to repaint his Wiltshire mansion and remove moss.

It is not just the Tories milking the system. Rising Cabinet stars such as James Purnell, Ed Balls and Yvette Cooper face accusations that they exploited loopholes in parliamentary housing expenses. Scan a list of 43 MPs who claimed ACA on a second London home and declared rent from a third last year and you quickly understand why no party is in a hurry to raise this issue. True, 19 of the names are Tories, but 15 are Labour MPs and seven are Liberal Democrats; so much for their squeaky-clean credentials. The other two represent Northern Irish seats: one a Nationalist and the other a Unionist.

The housing allowance scandal is only one part of a much bigger story. From foreign junkets to the employment of relatives, from party funding to the £165-a-night peers' subsistence allowance, there is the stench of sleazy self-enrichment. And now, as these people debate the clampdown on public-sector pay and a crackdown on benefits cheats, comes the howl that their salaries should be increased. Some have made the outlandish suggestion that the way to tackle abuse of the ACA is to incorporate the maximum sum available into MPs' basic pay, giving them all a £22,000 pay rise. This would, in effect, be a reward for errant behaviour.

Clearly, our parliamentarians are in no mood to clean their Augean Stables. The other non-solution has been to hand the matter over to an inquiry, chaired by the Speaker. This is doubly unconvincing. Firstly, the majority of the members on this panel have themselves faced serious accusations (one even purchasing a quad bike from the public purse). And secondly, the Speaker himself does not exactly have an unblemished record on this front, nor is he renowned as a supporter of transparency and freedom of information.

So what should be done? Ideally, there should be a rapid, genuinely independent inquiry conducted by trusted advisers. This could be established under the Committee on Standards in Public Life, set up under John Major. Significantly, it has been kept out of the fray on the grounds that the Speaker's inquiry is already looking into expenses. But if Parliament does not put its house in order quickly, MPs will rightly be blamed for the continuing decline in their standing.

We must hope they are not too blinded by greed to understand the peril that they face.