Serial murderers trapped through traces of their DNA, 'cold' cases solved after 30 years - this is the stuff of front pages and TV drama. But, beyond the headline-grabbing cases, DNA profiling has become a routine tool in tackling crime. At its heart lies the burgeoning National DNA Database, the NDNAD, set up in 1995 and on target to contain the DNA profiles of all 2.6 million 'active criminals' by 2004.

With support from the Wellcome Trust's Biomedical Ethics Programme, Dr Robin Williams, Senior lecturer in Sociology at the University of Durham, is conducting the first in-depth study of the NDNAD, together with colleagues Dr Paul Johnson at Durham and Dr Paul Martin in Nottingham. Their study will chart the history of its expansion, exploring the scientific, legal and social aspects of the database and the ethical issues it raises. "The NDNAD is the first of its kind in the world, extraordinary both for its scale and the rapidity of its expansion."

It was in 1999, while working on a sociological study of crime scene examiners (who are responsible for collecting crime scene evidence), that Dr Williams witnessed the project taking off. "I could see the intensification in the use of DNA evidence and the database - and how much effort the state was focusing on this area." He was curious why "while high profile cases and non-criminal uses of DNA samples had attracted a huge amount of attention and debate, this major area had been largely unexplored. Public attitudes have been tested, but awareness of the database's scope is still poor".

The NDNAD comprises DNA profiles derived from 'crime scene stains' (material collected at locations where crimes have been committed), and 'Criminal Justice samples' (taken from everyone arrested on suspicion of involvement in a recordable offence). The police have the power to take and use Criminal Justice samples without consent. The claim is, there is a 70 per cent chance that a crime scene stain can be matched to a Criminal Justice sample. For the Home Office, "the database is a vital weapon in law enforcement helping to remove thousands of repeat criminals from circulation". While Dr Williams is cautious about such claims, he stresses that there is little doubt DNA databases help to focus the criminal investigation process, by excluding some 'usual suspects' and including others who might not otherwise have been checked. This must save time and money.

Through interviews and documentary evidence, Dr Williams aims both to track how people and organisations throughout the criminal justice system have come together to establish and develop the database, and to consider the ethical and social policy issues that have arisen in the course of its continuing development.

Key debates revolve around the retention of samples and their future use. The Criminal Justice and Police Act (2001) allowed the indefinite retention of DNA samples from all criminal suspects - "a big step", says Dr Williams. Last year, campaigners used the Human Rights Act to challenge the police's right to do so where no conviction resulted. Judgement came down on the side of the Home Office.

Should the Forensic Science Service have the right to allow further tests on this genetic material? Sir Alec Jeffreys recently warned: "Where there is a crime scene sample but no suspect, we can now try to learn something of the suspect from that DNA. There are tests coming along for hair colour, eye colour; one could imagine skin colour ... ethnic status or origin of an individual. Does the system become open to discriminatory abuse?" Williams echoes this concern: "A recent case, solved after 30 years, used the DNA profile of a relative to track down a killer. What does this imply for the future?

"What we are doing now would not be possible in societies in which citizens have less trust in state authorities. We need to consider the possibility that the NDNAD becomes a comprehensive genetic database not only of offenders, but increasingly of suspects - and perhaps eventually of citizens.

"The fact of state ownership of a person's unique biological marker clearly functions as a way of extending surveillance over his or her subsequent activities. The NDNAD objectifies a new kind of identity, that of 'criminal suspect'. Once your genetic presence is on the database, this constitutes an in-eradicable part of your identity."

Related links

• Biomedical Ethics grants: Further details on grant schemes

See also

• Dr Robin Williams at the University of Durham: Research interests including further information on the NDNAD
• Criminal Justice and Police Act (2001) published by Her Majesty's Stationery Office (HMSO)