MPs just don’t get it. They happily accuse the media of bringing politics into disrepute and then they go and do something so unutterably stupid that the public must wonder whether they have any contact with reality. So it was on Friday, when MPs voted to exempt themselves from the Freedom of Information (FOI) Act on the feeble grounds that they were protecting the interests of their constituents. A private member’s bill proposed by David Maclean, a former Tory chief whip, was voted through by a dishonourable alliance of Labour MPs, ministers and Conservative backbenchers. Efforts by opponents of the bill (all praise to the Liberal Democrats) to talk it out failed when the Speaker cut short the debate.

There is no case for exempting the Commons from FOI. Any issues of confidentiality that arise from MPs’ correspondence with constituents are covered under data protection legislation, as MPs know only too well. Their real aim is to prevent voters knowing what they get up to. If this bill becomes law, the requirement for MPs to reveal their expenses will be at the discretion of the authorities and could be removed at any time. Mr Maclean has not even defended it in the Commons and has refused to justify it on air or in print. This is parliament at its worst. The very people whose actions and conduct should be most open to public scrutiny are doing their best to restrict it.

Where was Gordon Brown, the prime minister in waiting, in all this? On Thursday evening, those lucky enough to be in the Labour party’s address book received an e-mail from Mr Brown saying that one of his main priorities would be “building trust in our democracy”. Less than 24 hours later, Mr “Macavity” Brown was well away from the scene of the crime when MPs voted to keep their affairs secret. According to his spokesman: “If MPs have voted this measure through then that is a matter for them.”

The omens are not good. Jack Straw, Mr Brown’s campaign manager, last week wrongly attacked Richard Thomas, the information commissioner, for being prepared to “drive a coach and horses” through the relationship between MPs and their constituents. The chancellor fought tooth and nail to prevent disclosure of Treasury documents relating to his £5 billion annual raid on pension funds in 1997. Papers on his decision to sell Britain’s gold reserves at the bottom of the market have yet to be released, thanks to Treasury resistance.

The fact is that this government has been doing its best to neuter FOI to the point where secrecy is once more the norm in public life. Lord “Charlie” Falconer is trying to push through changes that will make it much easier for the government or public bodies to reject requests for information on the grounds of cost. Media requests and those from campaigning organisations would quickly fall foul of the new rules.

Freedom of information has been one of this government’s better reforms, opening up public bodies to more scrutiny than would otherwise have been the case. If the media has been in the forefront of FOI requests, that is as it should be; its role is to get information and disseminate it to the public, which can then make up its mind. For a government so profligate with public money, to argue for restricting FOI on cost grounds would be laughable if it were not so serious.

It is not too late for Mr Brown or indeed David Cameron to change their minds. The word should go out to Labour and Tory peers in the Lords to kill Mr Maclean’s bill and ensure that it stays dead when it returns to the Commons. Mr Brown must insist that Lord Falconer’s consultation on FOI has only one result – that the status quo is preserved. Voters will not easily forgive MPs for changing the law so that they can hide matters that should be public. And they will not easily forgive another prime minister who promises to be whiter than white and restore trust in politics, only to do the opposite.