John Rentoul: Diskgate isn't Gordon's fault, but he'll still pay for it

Some of our megabytes are missing, and in the long run our politics, if not the Prime Minister, will benefit

David Davis, the shadow home secretary, describes it as "the worst and most catastrophic loss of data in the history of humankind". That is the kind of hyperbole that brings us up short. Does he mean that the case of the missing HMRC disks is more serious than the time that Nebuchadnezzar could not find the Assyrian tablets? Worse than the Dead Sea scrolls, mislaid for 1,900 years? Worse than T E Lawrence leaving the manuscript of The Seven Pillars of Wisdom at Reading station? Or what?

By going over the top with such abandon, in a GMTV interview to be broadcast this morning with my illustrious colleague, Steve Richards, Davis has achieved what no one else has dared attempt. He has made the disappearance of a copy of the entire child benefit database seem trivial. Set against the rise and fall of civilisations, a couple of CDs gone astray seems hardly more important than the daily drama played out in millions of households. "I know I put them somewhere. Keep looking."

Actually, it is quite likely that the disks will be forgotten in six months' time. It could be argued that, even if they do fall into the wrong hands, the risks of fraud or child abduction are only imperceptibly increased. There are other ways in which fraudsters and paedophiles can get at most of the information on the discs – not so easily or in such quantity, of course. No one in Government wants to say that, though. They may not be brilliant at managing public services, but they know the drill when something goes wrong: 'fess up and eat humble pie. Nor are we commentators comfortable playing down the consequences of such a grade A blunder as this. The only people who can make Gordon Brown and Alistair Darling look good are the Conservatives, by going too far.

Davis's exaggeration invites us to ask why we should think that a Conservative government would be any more competent in running public services. We should not. That was a point made in the Commons last week by the Prime Minister, who pointed out that the Conservatives proposed at the last election to save £660m by the "rationalisation of data processing" at HM Customs and Excise. David Cameron brushed this aside, saying that "to try and blame the Opposition is pathetic", but it was absolutely right. If, as some Tories tried to suggest, cost-cutting was a cause of the trouble, then they have an ideological disposition to make matters worse.

Unfortunately for Brown, none of this matters. A stray sentence of lunacy from Davis cannot turn a tide of public indignation. Making a valid argument that this is the sort of mistake that could happen under a government of any party cannot hold the waters back.

Last week's revelation that some of our megabytes are missing may not have much purchase on the history of humankind, but it feels like a historic moment in British politics.

It will have two distinct effects. First, it will improve public policy and the administration of public services, regardless of which party is in government. Second, it makes it more likely that that party will be the Conservatives.

Ministers, whether Labour, Conservative or coalition Liberal Democrat, will take a renewed interest in the difficult question that came to obsess Tony Blair. How to ensure that, when they pull levers in Whitehall, the cogs and chains elsewhere in the machine do what they expect. The disk débâcle was not a failure of procedure but a failure to follow procedure.

There are two ways of responding to that. One is better management – for which the model is the Passport Office, which was turned round by an outstanding boss, Bernard Herdan, when Blair and Jack Straw, Home Secretary at the time, focused on it. The other is to design out problems.

Last week I went back to the Hansard report of the House of Lords for 18 July of this year. Andrew Adonis, one of the most able ministers in this Government whose retention by Brown was one of the better decisions of the new administration, defended the plan – with which I cannot believe he is comfortable – for a national register of all children in England. This register, called ContactPoint, was supposed to become operational next year. With any luck, it will be the first victim – long before we get to identity cards – of the HMRC blunder. Most of the peers that spoke in the debate, as opposed to those that voted, were opposed to the register. Lord Adonis tried to reassure them about security: "All data are secured by encryption or scrambling while moving between computer systems, so that anyone trying to monitor communications will not be able to see the information."

And he was talking about a database that will have 330,000 people authorised to access it. There were obviously more people able to access the HMRC child benefit database than there should have been, but nothing like that number. There is simply no way that the confidentiality of the children's register can be safeguarded sufficiently.

So ContactPoint should go, and the plans for identity cards will focus more and more on those elements for which public support is robust: immigration control and biometric passports – which the US has insisted on but for which the deadline has been repeatedly postponed. Ministers, meanwhile, will take a much closer interest in the management of public services.

It is quite possible, therefore, that in six months' time, the missing disks will be largely forgotten and no one will have suffered. On the contrary, the general public will have gained because over-ambitious government computer projects will now be subjected to the sort of sceptical scrutiny that they should have received long ago.

Yet if the story of the disks is forgotten, the impression of incompetence will not be. That is unfair, but then so was the destruction of the Conservative record of economic competence after Britain's ejection from the European exchange rate mechanism in 1992. Membership of the ERM was a policy supported by the Opposition and much of the media. Ending it was a boon to the economy, laying the foundations of 15 years of steady growth. Yet, as Alan Watkins observes on page 47, it was the Tories that suffered.

The disappearance of two CDs in the internal mail is not as great an event as the ERM crisis – let alone a blip in the "history of humankind". But it is a part of a theme of incompetence, running from Northern Rock, revised statistics on foreign workers and illegal immigrants working as security guards. In none of those was Gordon Brown to blame, but he will suffer.

Further browsing on the Stop ID cards and the Database State website: http://www.no2id.net