Civil liberties campaigners have accused the government of creating a national DNA database "by stealth".

The number of records held has doubled in two years and a further million are due to be added in the coming year.

Home secretary David Blunkett said the importance of DNA profiling to criminal detection is more important than the civil liberties objections.

"Every week our national DNA database matches over 1000 DNA profiles taken from crime scenes with names on the database. Around 42 per cent of those matches are turned into detections within an average of 14 days. That is a huge achievement."

However, Gareth Crossman, a spokesman for civil rights group Liberty, said the government was "hell-bent on creating a national DNA database by stealth".

"It claims that only criminals will be listed, yet is passing legislation so DNA samples will be retained indefinitely for anyone who is ever arrested, whether guilty or innocent," he added.