Information on the number of prosecutions in which DNA subject sample profiles on the National DNA Database (NDNAD) taken from persons with no previous convictions have been used in evidence is not available from the NDNAD, nor is it available from police force data collected by the Home Office on forensic activity and related detections. The NDNAD holds DNA profiles taken from persons arrested for a recordable offence but does not hold data on their criminal histories; this information is held on the Police National Computer (PNC).
Some research information is, however, available on the number of DNA profiles taken from those arrested but not charged and from those arrested, charged but not convicted of an offence that have resulted in a DNA match, thus providing the police with an intelligence link on the possible identity of the offender and assisting in the detection of crimes. In April 2004, an amendment to the Police and Criminal Evidence Act (PACE) 1984 came into effect which enabled the police to take and retain DNA and fingerprints from persons who had been arrested for a recordable offence. In the period April 2004 to December 2005, the retention of DNA profiles of arrested persons who had not been charged or proceeded against had resulted in matches with crime scene profiles from over 3,000 offences.
In May 2001, an amendment to PACE 1984 came into effect which enabled the police to retain DNA samples taken from persons who had been charged but not convicted of an offence. In the period May 2001 to December 2005, an estimated 200,000 DNA samples taken from people charged with offences had been retained on the National DNA Database, which would previously have had to be removed because of the absence of a conviction. From these, approximately 8,500 profiles of individuals have been linked with crime scene profiles, involving nearly 14,000 offences.