Britain's government was accused Tuesday of breaking a promise to stop keeping the DNA records of people arrested for crimes but later found innocent.
Britain's DNA database is one of the largest in the world, containing genetic profiles of more than five million people, or 8 percent of the population. Samples are taken from everyone arrested for a crime, and the information is usually retained even if the person is acquitted or freed without charge.
Critics of the practice _ including Alec Jeffreys, the scientist who discovered DNA fingerprinting _ say it unfairly taints hundreds of thousands of innocent people with the suggestion of guilt.
After an outcry from civil libertarians and a ruling from the European Court of Human Rights, the government last year promised to delete the DNA profiles of up to 1 million innocent people.
Legislation outlining how that will be done is currently going through Parliament.
But a government minister has said that while the physical DNA samples of innocent people will be deleted and their electronic profiles removed from the country's central database, some profiles could still be kept by local forensic science labs, albeit with the names removed.
A Home Office spokesman said that is because the profiles of the innocent are stored at the labs alongside those of convicted criminals and it would be "impractical" to sort them out.
But blotting out suspects' names would not necessarily be irreversible. In the letter obtained by the Daily Telegraph newspaper, Home Office Minister James Brokenshire acknowledged that it would still theoretically be possible to trace each sample back to an individual because they were each tagged with an identifying bar code.
The Home Office spokesman, speaking on condition of anonymity in line with government policy, said that under the proposed new law it would be a crime to try to connect the profiles to individuals.
Privacy group Big Brother Watch accused the government of a "disgraceful U-turn."
"Destroying physical DNA samples is a pointless gesture if the computer records are to be retained," said the group's director, Daniel Hamilton.
But the government insisted it was keeping its promise.
"Our position has not changed at all. We will retain the DNA of the guilty, not the innocent," the Home Office said in a statement. "That means DNA records of the innocent will come off the database and physical samples will be deleted."