Andrew Grice: The Week in Politics

Something odd happened at Westminster this week. At the very last minute, the House of Commons decided to appeal against a Freedom of Information tribunal ruling that the "second homes" allowances of 14 prominent politicians should be disclosed. It is an important test case which could lead to the publication of all MPs' expenses.

You might think the attempt to prevent disclosure was not surprising. But some of the people involved were genuinely surprised by it. David Cameron, one of the 14, was told his mortgage arrangements were about to be all over the newspapers. The Tory leader was relaxed, having spent almost all his £22,000-a-year allowance on his constituency home in Witney (and not on food, a plasma TV or designer kitchen like some MPs). Suspecting the revelations would dominate last Tuesday's news agenda, the Tories decided not to announce anything themselves.

The decision to appeal was taken first thing on Tuesday morning by the House of Commons Commission, chaired by the Speaker Michael Martin, otherwise known as the "Commons authorities". I understand that only one other member – Harriet Harman, the Commons leader – was present at a hastily-convened meeting as the deadline for an appeal approached. The other members – Tory MPs Theresa May and David Maclean, Labour's Sir Stuart Bell and the Liberal Democrats' Nick Harvey – were still making their back way to Westminster after the Easter weekend.

Ms Harman's involvement is significant. Labour sources tell me the appeal was approved "at the highest level", which means that Gordon Brown wanted it. It seems the Prime Minister wanted to kick the issue into the long grass. The High Court case will not be heard until the autumn and there could be another appeal after that.

It is true that the commission received a second legal opinion that an appeal might succeed, conveniently contradicting its previous advice. It is also true that many MPs are unhappy about the tribunal's ruling that their private addresses should be published, which raises legitimate security concerns. This was the reason the commission gave, although I have looked at the High Court documents and they tell a different story. The "first ground of appeal" is that the MPs "had no reasonable expectation" their expenses would be disclosed when they claimed them (which looks to me like clutching at straws). The "second ground" is that publication of their addresses would be an intrusion of privacy and there were "special security reasons" why this should not happen.

Whoever called the shots, many MPs are appalled by the appeal. When Labour's David Winnick tried to voice their concern in the Commons, he was muzzled by the Speaker on the grounds that the matter was sub judice.

Heather Brooke, a freedom of information campaigner who is involved in the case, said: "The Speaker has the discretion to allow this discussion on the House floor, and I can only assume he tried to stifle MPs' queries because he knows that the reasoning behind the High Court appeal will not stand up to legal (or even public) scrutiny."

Supporters of the appeal suggest a delay will enable the Commons to bring in a new, more transparent system of expenses, thereby sweeping the stables clean after the current controversy sparked by Derek Conway, the Tory MP who paid his two sons as researchers while they were at university. Mr Brown's approach, characteristically, is to argue that it is better to get it right than rush in a flawed new system.

But critics of the "long grass" strategy suspect senior Labour figures are merely trying to put off the evil day until embarrassing details of their "second homes" expenses are revealed. They insist that the delay merely prolongs the agony and the bad headlines, and that it is better to "take a hit now" than closer to a general election.

Labour MPs are worried that Mr Brown, whatever his role, will be the loser. Both Mr Cameron and Nick Clegg, the Liberal Democrat leader, have been quick to call for sweeping reform. They understand that, in the voters' eyes, MPs' expenses have become a symbol of what voters detest about our politicians.

Mr Brown reflects the traditionalist view that the overwhelming majority of MPs are not corrupt and went into politics with the very best of motives. On both counts he is right. But that doesn't avoid the need for urgent action on expenses. The wheels turn slowly at Westminster. The Commons' review of expenses will report in July. Its new rules will not take effect until April next year. Yet Mr Cameron will bring in new rules requiring greater disclosure by his frontbenchers this Tuesday. He hopes that Tory backbenchers will follow, even though some don't like it.

Either way, he wins. "This could be Cameron's Clause IV – a battle with his party's old guard," one Labour MP told me.

Mr Brown is well aware of the gulf between politicians and public. The danger for him is that he is on the wrong side of the argument over expenses, and will be seen as part of the ruling establishment. It is not enough for him to say he supports greater transparency but that expenses are "a matter for the Commons". He needs to grasp the nettle, and quickly.