Not so long ago, I blogged about the government’s stupid-and-scary response to the drubbing it got at the ECHR concerning the retention of genetic information gathered from arrestees.

It would appear that the police have managed to make the policy even more dispiriting than it was already: they’re arresting people in order that they can obtain their DNA.  Quoted in the Telegraph, an unnamed officer (and if I was going to say anything this imbecilic, I’d want to dissociate my name from it if at all possible as well) says

[i]t is part of a long-term crime prevention strategy. If you know you have had your DNA taken and it is on a database then you will think twice about committing burglary for a living.  We are often told that we have just one chance to get that DNA sample and if we miss it then that might mean a rape or a murder goes unsolved in the future.

Oh, come off it.  Notice how in one sentence he says that a DNA database is preventative – because that’s really how most criminals work, isn’t it, Columbo? – and in the next he all but admits that it isn’t.

Anders Sandberg has fun taking apart some of the government’s claims about the use of retained genetic information: he’s suspicious of the idea that 1 crime in 15 is solved using genetic information.  I agree with him that this does seem a bit high, but it’s not beyond the realms of possibility.  I can see how that might work – though it implies that the forensic science bods are remarkably busy with genes.

But the larger point remains this: while (as Anders admits) there might be a reason to have everyone’s DNA stored on the database, it’s not obvious either that it’d be all that good a way of preventing crime, or that it’d feature in the sort of world we’d want to inhabit anyway.