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DNA profiles on a print-out
The database has helped solve 32,200 crimes - 0.7% of all crime
The DNA of innocent people arrested in England and Wales should be held for no longer than six years, ministers are expected to say.
Last year the European Court of Human Rights ruled it was unlawful to keep indefinitely the profiles of innocent people.
The United Kingdom has the world's biggest DNA database.
Police say retaining samples has helped solve crimes. Human rights groups say the proposed change is not enough.
There are no reliable figures on how many crimes have been solved because someone cleared of one offence has been later linked to another solely through the unique genetic fingerprint obtained from their DNA.
One recent government figure suggests that less than 1% of all recorded crime is solved with the database's help - although most police investigations do not involve DNA at all.
The European Court ruling last year said the system in England and Wales breached basic rights because it allowed police to retain indefinitely the DNA samples of anyone arrested in an investigation, even if they were later neither charged nor convicted.
Northern Ireland's DNA database is administered separately but follows the same model and is therefore, in practice, also in breach of the European Court's judgment.
Scotland's part of the database was given the all clear because police delete DNA profiles of most people who are not convicted. In all four parts of the UK, police take DNA swabs from suspects shortly after their arrest.
Liberty's Shami Chakrabarti: The database is "way out of proportion"
The Home Office has already deleted the profiles of children under 10 years old to comply with the European Court's ruling, but has been considering how to deal with the rest of the estimated one million samples from people who have not been convicted.
Earlier this year it proposed time limits of six or 12 years depending on the nature of the crime for which a suspect had been arrested.
These figures were drawn from research by the Jill Dando Institute of Crime Science.
Its director subsequently accused the Home Office of basing the proposals on unfinished research which did not prove the case for any particular time limit.
The proposals being outlined later on Wednesday are expected to discount the 12 year figure and propose different rules for the under-18s.
But the Equality and Human Rights Commission said such a proposal would not meet requirements set by the court ruling that data should be held only when there were "clear, justifiable reasons" for doing so.
NATIONAL DNA DATABASE
* Profiles: 5.9m
* Individuals: 5.1m
* Estimated proportion of replicate profiles: 14%
* Estimate for people neither charged nor convicted: 20%
* Crimes solved with database's help: 32,200 (0.68% of all crime)
* Profiles removed March-Oct 2009: 255
Source: Home Office/Parliamentary questions
The shadow home secretary, Chris Grayling, told BBC Radio 4's Today programme a future Conservative government would adopt the system in place in Scotland, where DNA samples are kept for no longer than five years and in relatively minor cases destroyed at the end of the inquiry.
He added: "What I don't think we should be doing is saying to absolutely everybody who is pulled into a police station for any reason, 'Your DNA will be taken and it will be stored indefinitely,' as is the case at the moment, or indeed will be stored for up to six years as the government appear to be proposing'.
"One of the fundamental principles of our criminal justice system is that you're innocent until proven guilty and I think this actually rather undermines that principle."
Former detective Hamish Brown says the DNA database is an important tool
Julie Bindel, from the campaign group Justice for Women, told Today she understood the fears of discrimination against those whose DNA profiles are kept - but the needs of victims also had to be considered.
"It may be that we need to think about a national database," she said.
"It's something that we feel uncomfortable with, but so many crimes have been solved by DNA and so many crimes have also been solved by acquitting those who have been falsely accused - some of the worst miscarriages of justice.
"And I think for women particularly who've been raped and who don't get justice we have to balance their rights against the rights of those who don't like the idea of having their DNA on record."
Shami Chakrabarti, director of the campaign group Liberty, told BBC News: "The government has been stockpiling the DNA of completely innocent people including children and the more innocent DNA you keep the greater the risk of accident, error and abuse."
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