Crime and Security Bill

My hon. Friend the Member for Epsom and Ewell (Chris Grayling) is not in the Chamber, but I would have mentioned that if he had been. We too often take our understanding of what is happening in reality from popular culture, which the Home Secretary did today when he suddenly cited, out of thin air, one of his new examples—it was the first time we had heard about it—and talked about DNA under victims' fingernails. The truth is that the relevant DNA in most murders is not the perpetrator's, but the victim's. That is the blood that is found on clothes, in the car, on the weapon, or on the skin of the person who carried it out—usually a man, to go back to earlier statistics that we heard. The database has no implications for such cases, because the body is generally there. The most common circumstances in which DNA is used is when the criminal—the guilty man or woman—is identified first, with DNA taken second. In such circumstances, the database does not feature at all. The next category is when the DNA that is taken comes up as relevant to a cold case—we heard earlier from the right hon. Member for Birkenhead (Mr. Field), who is very keen on the issue of cold cases. However, the database has absolutely no implications for cold cases. The argument about cold cases is complete rubbish, because the relevant database for a cold case is that of cold case DNA samples from crime scenes, and there have not been more solutions of cold cases because that database is incomplete—and what is more, the Government propose to close Operation Stealth, the unit that runs it. If we really want to fix the cold case problem, we need to get the database of DNA from cold case crime scenes up to date, and then check DNA against that every time a person is arrested. I will return to how that has caused the House to be misled in a moment. The last category of DNA use is the one that is relevant to today's debate. It relates to future cases when a match is found to DNA that is already held, and an individual is arrested on the back of that. No one argues that that is not important. After all, not one person who has spoken has said that we should take guilty people—4 million of the 5 million—off the database. Both the Conservatives and Liberals argue that 2 million more such people should be put on the database, because that is where the system's power lies. That is because, despite what the Home Secretary says, every piece of scientific research that has been carried out on criminality is clear that criminals are almost always repeat offenders. Those who commit big crimes precede them by committing small crimes. Those who are socially undisciplined by committing one sort of crime are undisciplined on everything, whether that is stealing things, cheating on fines or not paying following driving offences. Some of the Government's more sensible strategies hang on that understanding. There is an enormous difference between the likely criminality of innocent people and those who have already committed crime. If that was not true, there would be a case for a national database. That was why the hon. Member for Eastleigh was right when he said that the Home Secretary had made the case for a national database. If the Home Secretary believes that the data should be there, they should cover all innocent people, not just those who are unlucky enough to get caught up by a random process. Let us think about the people who get caught. First, there are the victims, because if a person is mugged and the police happen to turn up on that occasion, the mugger will be much slicker than the victim by saying, "He hit me first." We have read in the newspapers and heard anecdotally about many such cases. Secondly, there are the have-a-go heroes who try to stop a fight but also get caught in this messy process. Then there are the children who are accused by another child, whom I mentioned earlier, and the teachers who are accused by a malicious child—there are two such cases in my constituency. There are also the care workers who are accused by people who are mentally unstable. They might have spent their lives trying to support those people but—bingo!—there is another case. All those innocent people are caught in this trap, yet we are doing what is convenient to the police. Frankly, the police gave disgracefully poor evidence to the Home Affairs Committee, and I recommend that hon. Members read GeneWatch's summary of the contribution of the representative from the Association of Chief Police Officers—almost every piece of data that he gave was wrong. To put it bluntly, ACPO's understanding of the statistics and probability is non-existent, and I am afraid that it is down to the House to insist that Government agencies do their job properly, rather than sloppily and in a way that impinges on the rights of the people whom they are there to protect. That all leads me to believe that there is a problem to be dealt with. As I said, the Scottish system is not perfect. However, I say to Ministers—they might have been discounting the rest of what I said, but I would like them to listen carefully to this—that in this area, there is a massive amount of data under the Government's control. The data are in a manageable, electronic, coded database form. It is possible to do a great deal to pursue the effectiveness of that database, yet we have seen almost no published data from it. The data that we have seen have been desperately flawed. Again today, we heard the Home Secretary conflate the issue of re-arrest with that of conviction after arrest, behaving as though being arrested twice somehow made a person guilty. To a young black man in Brixton, I do not think that that is true. It is no surprise if somebody who is on the database gets picked up again—how do we think policemen work? It is not wrong that they should work in that way, but it is simply wrong to draw that conclusion. A couple of months ago, I was so horrified by the Jill Dando Institute data that I asked its research director whether I could see the information and interview the researcher. Just 10 days later, the data were withdrawn because the same conflation error had been made. It is not hard to solve the problem. The Government have the information, and they should put it in the public domain, or at least in the domain of authorised academics who can examine it independently. Then we could get some sensible answers on the mathematics of the matter, so that we could judge how much freedom, privacy and presumption of innocence we should trade off against the right to security from violent criminals. This is a dangerous matter, because juries take DNA evidence as the golden bullet. Too many of them have watched "CSI", "Bones" or "Cold Case Files" and believe that DNA evidence is perfect. I shall ambush the Home Secretary on his way home on the train on Thursday and give him a copy of this week's New Scientist. I recommend that the other Ministers read it, too. It contains a long overdue piece about the doubts that many scientists have about the veracity of the presumption that there is a one in 7 million chance of DNA evidence being wrong. There are all sorts of reasons why that should not be the case, and I shall not bore the House with the technicalities today—my first degree is too long ago for that. It is likely that the probability of a mismatch is much greater than we think. We come up against what is known as the "birthday syndrome". The chance of me and the Home Secretary having the same birthday is one in 365—that is pretty straightforward to work out. The chance of me and one of the entire Home Office ministerial and Parliamentary Private Secretary team having the same birthday is about 25 per cent. If we add in the people in all their private offices, it is about 50 per cent. Actually, the chance of my having the same birthday as the Home Secretary is zero, because his is in May, but the point is that the probability of a mismatch rises steeply the greater the database gets. The presumption among those who are tied to databases is that the bigger the database, the better it will be. No, the bigger the database, the geometrically bigger the chance of a mismatch. That is the mathematics. Members should not believe me, they should go and get themselves a mathematician to explain it to them. It is straightforward, and it is called the birthday syndrome. A bigger database carries a greater chance of a mismatch. If a quarter or a fifth of those on the database are innocent, there is a serious risk of a miscarriage of justice. DNA is a powerful and effective tool, but we make an awful lot of presumptions if we jump to the conclusion that it is perfect. The Government are in a position to release the information from the database to the scientific community so that it can make the judgments that I have mentioned. The American Government have been approached to do that and turned down the request. I suggest that if the British Government really want to do something in their last few months in office, they should accede to it. They are right that DNA is a powerful tool that can protect British citizens, but it can also create serious miscarriages of justice. It is in their interest to ensure that that does not happen.