Suggestions that there should be a national database storing DNA samples from all citizens should be resisted. At present the police take DNA samples from everyone who has been arrested, and they store the samples regardless of whether the suspect is subsequently convicted. This database has provided evidence for the arrest and conviction of rapists and murderers. However, the database should contain the DNA only of those convicted of a sexual or violent crime. To store the DNA of innocent people is an infringement of the right to privacy of those who have never committed a crime. Moreover it is unnecessary, since the police need access to the DNA only of those convicted of a serious offence in order to solve cases of sexual and violent crime.