Andrew Grice: Farce or tragedy? Sadly, it is both

One Labour MP, Emily Thornberry, was sent a bath-plug in the post by a constituent angry that the Home Secretary Jacqui Smith had claimed 88p for one on her parliamentary expenses. Another Labour member, Alan Simpson, brandished a plug during a Commons debate, warning that Parliament's failure to tackle the big issues affecting people's lives had "degraded and devalued politics to the level of the bath-plug".

Farce or tragedy? It's both. Yesterday's embarrassing disclosures about the MPs' expenses claimed by 13 Cabinet ministers, including Gordon Brown, inflict more bruises on Labour at a time when the party and its embattled leader are already on the ropes. But The Daily Telegraph's revelations will also do more damage to the image of politics as a whole. The public's scepticism is now downright cynicism. Never mind the politicians; it's not healthy for the people.

Ministers fear that Labour will be hit hardest because it is the governing party. Labour's polling advisers say recent media reports about MPs' expenses hurt the Government much more than the storm over the plan by the former Brown aide Damian McBride to smear senior Tories. You can't really blame the voters: it's their money, after all. And that was before the present firestorm, which is bound to rage for days if not weeks.

Labour already faced a drubbing at the elections to the European Parliament and English county councils on 4 June. Now things can only get worse. When Labour folk talk down the party's prospects, they know they are going to a get a hammering.

Conservative and Liberal Democrat blushes will not be spared as more details are dribbled out over the next few days. The reaction of many voters will be a "plague on all your houses" on the grounds that all political animals have their snouts in the trough. "People have moved from apathy to antipathy," says Rob Hayward, an elections expert and former Tory MP.

A long-running expenses saga could dominate the June elections campaign. Worryingly, it could easily boost support for the far-right British National Party, which is trying to win its first seats in a nationwide election in the Euro poll. The revelations could be a timely gift to it. Was the Telegraph right to publish? The politicians who argue that all the information would have been issued by the Commons in July are wrong. The Telegraph has a public interest defence in that it needed to see the uncensored version – including MPs' addresses, for example – to work out the scams, such as the repeated switching from what is the "first" and "second" homes to maximise expense claims. Defending of what was probably a six-figure sum for a computer disc that someone, somewhere stole or copied, is harder to justify, though the paper will argue that the ends justify the means.

The fact that at least three other papers turned down the goods tells us something. So far, there is no sign of corruption or ministerial resignations. It's a fair bet that disclosure of similar material in most countries on the continent would make the Telegraph's scoop look very small beer. I don't believe many British MPs are in it for the money. The total cost should also be kept in perspective. Commons accounts show that MPs' salaries (at present £63,000 a year) cost about £56m annually, staffing allowances £55m and the controversial "second homes" allowance only £11m. The housing payments have generated a disproportionately large amount of headlines because the rules are open to abuse.

Greedy MPs have milked the system for all its worth, but within the rules of the club. They were poorly policed by Commons officials reluctant to doubt the honour of "Honourable members". But that is no excuse. Some of the overpayments and mistakes came to light only after the Commons authorities lost a freedom-of-information battle and MPs started to check their claims going back to 2004.

Mr Brown's instincts were right when he tried to bounce MPs into a snap decision on expenses reform two weeks ago. His plan to replace the £24,000-a-year "second homes" allowance with a daily attendance payment could have limited the damage. If it had not been scuppered by MPs, they could have argued that they had (just) killed off the worst aspect of a rotten system.

Unfortunately for Mr Brown, he tried to get personal credit for cleaning up the system, so didn't consult anyone first. If he had done, he might well have got a consensus for changing the "second homes" payments. But he was outmanoeuvred by an alliance of opposition parties and Labour MPs upset by not being told about his plans. That anger contributed to Mr Brown's first Commons defeat, over residence rights for Gurkha veterans. "The vote on the Gurkhas was revenge," one Labour MP said. The opposition to Mr Brown's plan to change the "second homes" payments is symptomatic of the Westminster culture which spawned the expenses system. It dates from the 1960s and 1970s, when allowances were boosted so MPs' pay could be held down as governments preached pay restraint to the nation.

MPs, too mindful of their own pockets, have been painfully slow to change that culture, and the rules on expenses they fix for themselves. Many say it is "the system" that is wrong, not their claims, as if "the system" has nothing to do with them. It has everything to do with them.