Unfortunately, many innocent people may have to face a non-criminal police record with their DNA on file. DNA should not be surrendered without due process, and even then, new issues need to be addressed in the ethical maintenance of a DNA data base by Government authorities.

DNA can serve not only as a criminal identifier, but as a unique blueprint to the person. Mr Blair needs to research and better understand the implications of the international Human Genome Project. This shows DNA to be an intensely personal identifier, capable of providing information on a person's genetic strengths and weaknesses.

In an imperfect world, medical treatment might be selectively applied to those whose DNA promises the best potential contributors to society. A future unscrupulous Government, or subversive group, might see an opportunity to conduct a covert eugenics program.

DNA should not be casually collected. An arrest on a potentially imprisonable offense as the basis for the collection of a DNA sample is a metric too easy to abuse. Even the samples collected to date are subject to potential abuse.

If Mr Blair wants to assist police without unduly compromising individual privacy, he should first solicit a study from a body represented by criminologists, and more importantly, by leading medical privacy ethicists.