The Big Question: What is the DNA database, and why do we have so many people on it?
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Why are we asking this question now?
Since its creation 11 years ago, ministers have taken great pride in the fact that this country leads the world in the creation of a national DNA database. But its rapid growth - it now contains genetic profiles of more than 3.6 million people, many of whom have never been convicted of an offence - is ringing alarm bells.
Sir Alec Jeffreys, a pioneer of DNA forensic science, has brought those fears into focus with a warning that the expansion is out of control. He condemned the "mission creep" behind the project, protesting that the database was never intended to include innocent citizens. The Nuffield Council on Bioethics, an independent think-tank, has also raised concerns that the country risks being transformed from a "nation of citizens" into a "nation of suspects".
The DNA database is just the latest example, civil liberties groups argue, of the gradual creation of a "surveillance state" by Labour. As evidence, they point to the proliferation of closed-circuit television cameras and plans for identity cards, underpinned by a national identity register.
What are DNA profiles and how are they taken?
Deoxyribonucleic acid (DNA) contains the genetic information unique to each living being. It is typically extracted from samples of saliva, blood, semen and hair. With the exception of identical twins, a human being's DNA is unique and the probability of a false match between two unrelated individuals is said to be less than one in one billion.
With the frontiers of genetic science pushed back over the past two decades - and courts ever more reluctant to convict on the basis of confessions - detectives have turned to the fast-developing technology with excitement. Non-intimate samples, usually a mouth swab, can be taken by police without consent, while consent has to be given for taking blood.
Why has the database developed so quickly?
The last Tory home secretary, Michael Howard, established the world's first DNA database, which is based in Birmingham. But the principle has been enthusiastically embraced, and developed, by Labour. Nearly four years ago police were given the right to obtain and retain DNA from anyone arrested, regardless of whether they are eventually prosecuted or convicted.
The legislation, which received very little publicity because it was announced on the second day of the Iraq war, has had the effect of dramatically accelerating the collection of samples.
Forty thousand profiles are added to the database every month and today some 6 per cent of the population - and far higher proportions of young men and ethnic minorities - are on record. That compares with an average just over 1 per cent in other European countries and 0.5 per cent in the United States. The genetic information remains on file for a person's life and is almost impossible to remove. The practice in England and Wales contrasts with Scotland where an individual's DNA details are removed if they are acquitted.
Suspicions are growing that the Government wants to create a national DNA database of every adult. They were fuelled last month when Tony Blair said he believed the number on the "database should be the maximum number you can get".
What safeguards are there against abuse?
An unnamed "custodian", based in the Home Office, has responsibility for controlling the quality of the database and for limiting access to its contents. In addition, a board bringing together Home Office officials, police chiefs and police authority members monitors its development.
The Home Office says its contents "can only be used for the prevention or detection of crime, the investigation of an offence and the conduct of a prosecution". However, the department has come under fire for allowing EU police forces to examine its records. It insists that sharing information helps the fight against international crime, but critics fear it could ultimately mean losing track of who has access to confidential data. There was also a report this year that one of the six private companies used by police to analyse DNA is keeping copies of the results rather than destroying them.
Do DNA profiles help catch criminals?
DNA is successfully obtained at less than 1 per cent of crime scenes. But according to the Government, it is still having a significant impact, with the presence of DNA sharply increasing the chances of solving a crime. The crime detection rate last year was 26 per cent; where DNA evidence existed it rose to 40 per cent.
Recent advances in DNA technology have also allowed police to reopen their investigations into scores of unsolved "cold cases". This work, Operation Advance, has so far led to 21 convictions with sentences handed out to date totalling more than 100 years as well as three life terms. Those who have been tracked down include James Lloyd, the South Yorkshire "shoe rapist", who was convicted for sex attacks in the 1980s after his sister gave a DNA sample when she was stopped over a driving offence.
Police also argue that the database is a useful tool for ruling out the innocent from their inquiries.
Should innocent people worry about the database?
At the heart of this debate is the balance between protecting the civil liberties of the population and increasing its security against violent crime. Without doubt, worrying anomalies have been created by the rapid growth of the DNA database.
There are 24,000 under-18s in the United Kingdom who have committed no crime and have not even been in the court, but whose DNA is being held in the database. They include an 11-year-old whose DNA was taken during an armed robbery investigation and a Northern Ireland girl who was caught writing her name on a wall.
At least one third of young black men have had samples taken, many after being targeted through stop-and-search legislation. That is more than 10 times the proportion of Afro-Caribbeans in the population at large. This disparity both reinforces and results from a stereotype that black people are more likely to commit crimes than white people.
The civil rights group Liberty says Britons are now the "most spied-upon people in Western Europe", and all innocent people on the database could reasonably ask what entitles the state to retain private genetic information about them.
Is this a price worth paying for the fight against crime? And could it be right that this quiet revolution has happened with virtually no public debate?
Should the police be allowed to keep the DNA of innocent people?
Yes...
* Where DNA evidence exists, the chance of solving a crime improves by more than 50 per cent
* A string of 'cold cases', including murders dating backing two decades, have been cracked
* Innocent people have nothing to fear from the database - and can be ruled out of investigations
No...
* The innocent have a fundamental right not to have their details included on a criminal database
* Disproportionate numbers of young people and ethnic minorities are on record
* The confidentiality and security of any database - particularly one that is rapidly expanding - is hard to guarantee