The development of liberties in English law is very much the story of limits being placed upon state power. One element of those liberties is that there should be limits placed on the information which the state can demand from its citizens and keep on its files. ID cards are one major infringement of that principle, and a DNA database is another. The police have been empowered to collect and hold DNA samples from people who have not been convicted of any crime. Even suspicion can be deemed sufficient, and over-zealous police forces have developed the practice of taking DNA samples for quite trivial offences.
Some police officers have said that they wish the DNA database to include as many as possible, and some forces even have DNA samples held on file for thousands of children not even accused, much less convicted, of any crime. Our DNA contains much evidence about our lives, including our vulnerability to specific diseases, and even aspects of personality that is no business of the authorities. The widespread collection and retention of such information is an abuse of state power, and should be stopped. It is part of the creeping erosion of our liberties that police feel entitled to treat citizens as potential criminals, and collect and hold information on innocent people that they have no business with.