Alan Johnson on DNA retention – a quick fisk

The Home Secretary Alan Johnson has today written a short defence of the practice of retaining innocent DNA on the national database for six years. You can read the article in full on the Guardian Comment is Free, but we thought we'd pick out a few choice cuts and show why his reasoning is faulty, unreferenced and internally inconsistent.

"The most recent research supports the case for the retention of DNA profiles of those arrested but not convicted. It also shows that, after six years, the probability of re-arrest is no higher than for the rest of the population."

AlanJohnsonBlue It is a shame that the Home Secretary did not reference this research, because it would have certainly helped his argument. I am left to speculate that the research might be that conducted by the Jill Dando Institute, whose Director came forward last month to admit that the Government has pressured the Institute into a figure and ended up basing their DNA policy on incomplete research. 

This might also explain the inconsistency in his argument; because if the evidence suggests that after six years those people whose DNA is retained on the database are just as likely to commit a crime as those who are not, where are the benefits of retention?

"I reject the claim by the Human Genetics Commission yesterday that large numbers of people are being arrested simply to collect their DNA. There is no substantive evidence to suggest this is so."

Except, as we wrote yesterday, the claim was made by a former senior police officer and there are constant streams of stories peppering the newspapers of people being arrested for spurious crimes and having their DNA taken.

"this accepts that there should be retention where there is no charge, while ignoring the evidence that three (or even five) years is too short a period. The Scottish model is said to be a success, but by whose standards, and by what evidence?"

Yet again we are left wanting the research that shows that 3 or 5 years is too little (more to the point Scotland regularly delete DNA profiles if the subject is completely innocent) but these 'standards' are those of the European Court who, when ruling that the system in England and Wales was "blanket and indiscriminate" and "could not be regarded as necessary in a democratic society", described the Scottish system as "fair and proportionate".

"It is not a clear-cut choice between liberty and security – between siding with the civil liberties lobby or the forces of law and order. The far less headline-friendly reality is the need to balance all these factors – protecting the public, but in a way that's proportionate to the threat. I believe that the government's proposals do precisely that"

The law and order defence continues to look shaky (as previously reported, between 2004/5 and 2006/7 the number of profiles added doubled while recorded detections fell by 20%). By contrast there are a number of stories of people being discriminated against for having their DNA on the database and several reports from the US highlighting the fallibility of DNA evidence. Then there is the equally concerning rates of data loss and the fears of what happens when the wrong people get their hands on our biometric details.

The Minister quotes several cases in which the DNA evidence was critical in securing convictions, but we all know that the police frequently solve crimes committed by people who have never given a sample. Yet again this is a policy driven by political expediency, research we can't read and the desire to be 'seen to be doing something' with little consideration of the wider consequences.

By Dylan Sharpe

Posted by on Nov 25, 2009 in DNA database | 4 Comments


  1. Claire
    25th November 2009

    I have been trying to find out if I’m on the NDNA database. The home office told me to ask the police, but the police have already told me they don’t administer it. The home office then said they don’t know who administers it, and they don’t know how to find out either. When I said this wasn’t really acceptable, they then told me it’s the NPIA. Seems like a shambles to me. When I rang the NPIA, they wanted to know how I know about the DNA database. When I replied that it is public knowledge, and enquired why they would ask such an odd question, the man said he didn’t know, but that it was a standard question he’s obliged to ask. What is *that* about? I’m still none the wiser about my DNA.

  2. Guy Herbert
    26th November 2009

    Perhaps because BigBrotherWatch is yet young, and you haven’t the long experience necessary to interpret that strange dialect of half-truth in which all Home Office statements are made, I think you miss an important point or two in that first quote.
    Being positioned as it is, the sentence, “It also shows that, after six years, the probability of re-arrest is no higher than for the rest of the population.” might lead you to believe that there is a contrast being drawn, against the preceding sentence. That the preceding sentence contains an assertion that before six years, there is a higher probability of re-arrest. There isn’t such an assertion. We don’t in fact get anything from the know *how* “the most recent research” supports retention, even if a re-arrest within six years might do so (rather than the quite plausible hypothesis that police frequently arrest the usual suspects).
    Note also that you have been mislead by the word “re-arrest” being used in that spurious shadow of a contrast, into assenting to the Home Office’s presumption that someone who is (re)arrested is guilty of a crime.
    If the Home Office actually had quantifiable evidence that retained DNA produces significant numbers of convictions as a result of DNA-driven detection during any arbitrary period after sampling (which is what logically the retention case requires), then it would produce it, or at least positively claim it, rather than offer a rhetorically crafted juxtaposition of negatives. Conclusion: there is no evidence. (Ben Goldacre memorably demolishes the purported case, as put forward at the beginning of the year, here: //
    But the Home Office having dropped that, have replaced it with… nothing at all.)
    Why six years? My guess: Because it takes a fraction longer than that to fight all the way to the ECHR, so that reduces the likelihood anyone will have this new fallback position overturned for a while.
    Meanwhile, of course, the ACPO has yet to fall back. It is still keeping DNA indefinitely until there is ‘appropriate’ legislation, which happily for it was actually most of a year by the abortive consultation.

  3. guy herbert
    26th November 2009

    Sorry, a lot of mangling in the edit there. Last sentence should be: It is still keeping DNA indefinitely until there is ‘appropriate’ legislation, which happily for it was actually *delayed* most of a year by the abortive consultation.

  4. Marie
    27th November 2009

    I’m not sure geting rid of the police DNA data base would solve a problem since we (self and spouse) just received our invitations from the DOH to “take part in a major medical research project called UK Biobank” and taking part means “you agree to have your samples stored by UK Biobank and used… for many years”
    Ok so i’m paranoid, but all the same….