DNA database pollution

Lord Justice Sedley may be a senior judge, but he is clearly not an expert statistician, (your report 5 September).
By The Newsroom
Published 8th Sep 2007, 01:00 BST

DNA profiles recorded on the national DNA database do not uniquely identify an individual. Matching relies instead on a genetic fingerprint comprising ten points. As the number of people on the database increases, there is a corresponding increase in the number of people likely to match any particular profile and hence a reduction in the usefulness of the database for identifying suspects.

Polluting the DNA database with profiles from innocent people will be counter-productive for law enforcement purposes, leading to trial by database and so infringing the right of citizens to be presumed innocent.

GERAINT BEVAN

Grovepark Gardens

Glasgow