I agree wholeheartedly with R Waite (Letters, August 11) that a compulsory national DNA database is, on the whole, a good idea.

It would potentially help to prevent and solve a wide range of crimes, from Islamic terrorist atrocities to the wave of muggings and assaults in York which seem to be escalating at a frightening pace.

But there would need to be safeguards.

Just as fingerprint evidence has been tampered with, there is the risk that either corrupt policemen or other criminals would seek to plant DNA evidence at the scene of a crime in order to get innocent people convicted.

The potential for miscarriages of justice is a lot greater, because DNA evidence is widely believed to be infallible. There is also the risk that government and law enforcement agencies could seek to use the database for more sinister purposes than crime detection. For that reason, I should argue for a DNA database maintained by an independent agency.

The police would need individual permission to search it from a magistrate for each investigation, using a similar system by which they now obtain search warrants.

To protect against data crime, the database should not be physically connected to the internet or any other telecommunications network, and all of its employees should be required to sign the Official Secrets Act.

Unlike many in the civil liberties brigade, I do not feel that the risk of abuse is a valid reason in itself for society not to equip itself with a tool that would almost certainly achieve a radical reduction in crime.

But there does need to be an effective system of safeguards put in place alongside it.

Leo Enticknap,

Ingram House,

Bootham,

York.

Updated: 10:26 Monday, August 15, 2005