Police guidelines allowing forces to retain the fingerprints and DNA samples of innocent people are unlawful, a panel of leading British judges ruled today.
The ruling was made by the Supreme Court in London nearly three years after the European Court of Human Rights reached a similar conclusion.
Judges said Government plans for changes to the law were already in the pipeline.
The 1984 Police and Criminal Evidence Act required the destruction of samples and fingerprints "taken from a person in connection with the investigation of an offence if he was cleared", said judges.
But the law changed in 2001 and gave police the discretion to retain samples "after they have fulfilled the purposes for which they were taken".
The Association of Chief Police Officers (Acpo) had gone on to issue guidelines saying "data should be destroyed only in exceptional cases", said judges.
A panel of seven Supreme Court justices today concluded, by a five to two majority, that those Acpo guidelines were unlawful because they did not comply with European human rights legislation on rights to privacy.
The Supreme Court - the highest court in England - made the ruling in allowing appeals by two men who said police in London had unfairly retained their fingerprints and DNA samples.
Judges at the European Court of Human Rights made a similar ruling in December 2008 after allowing appeals by two men from Sheffield, who also said South Yorkshire Police had unfairly retained DNA samples.
European judges were asked to rule on the Sheffield cases after judges at the House of Lords - then England's highest court - rejected appeals, saying retention of DNA samples did not breach European human rights privacy laws.
Judges today said the Acpo guidelines did not cover forces in Scotland, where samples could be kept only for a limited period and for certain crimes.
They said ministers were looking to create new laws to bring England and Wales into line with Scotland.
"Whether and in what circumstances the police should be able to keep the DNA samples and profiles, fingerprints and photographs of people who have been arrested but not convicted is a deeply controversial question," said one Supreme Court Justice, Lady Hale, in today's judgment.
"The Government is promoting the Protection of Freedoms Bill, which will adopt in England and Wales the present system in Scotland. This allows retention only for a limited period and in respect of certain crimes.
"It reflects a strong popular sentiment that the police should not be keeping such sensitive material relating to 'innocent' people, even if they are allowed to use it 'for purposes related to the prevention or detention of crime, the investigation of an offence, the conduct of a prosecution'."
She added: "If the popular press is any guide to public opinion, the (2008) decision of the European Court of Human Rights ... is one which captures the public mood in Britain much more successfully than many of its other decisions."
Judges said opponents of police being allowed to keep the fingerprints and DNA of innocent people argued that:
* "Agencies of the state" could not be trusted to use such information "only for permitted purposes".
* The premise that people who had been arrested were more likely to offend in future was "unsustainable".
* Black and ethnic minority men were more likely to be arrested and therefore more likely to have data unfairly kept.
* The "stigma" suffered by someone whose records were kept - plus wider concerns about potential misuse - outweighed any benefits in the detection and prosecution of crime.
Judges said police and supporters of data retention argued that:
* "Agencies of the state" would not misuse information for "sinister" purposes.
* Police would not solve some serious crimes because destruction of records would prevent investigators getting "hits" on databases.
* Any "stigma" felt was irrational.
The two men at the centre of today's appeals were not identified - for legal reasons - in the Supreme Court judgment.
Judges said one was arrested in 2007 on suspicion of assaulting his girlfriend but never charged. The other was arrested in 2009 on suspicion or rape, harassment and fraud. He was acquitted of rape after prosecutors offered no evidence and was never charged with harassment or fraud.
In the Sheffield cases, judges said Michael Marper, who was 45 in 2008, had been arrested in 2001 and charged with harassment before the prosecution was dropped and a 19-year-old man, who could not be named, had been charged with attempted robbery in 2001, when he was 12, but later cleared.