The report recommends that police stop automatically taking DNA samples in England and Wales when someone is arrested and says that they should be given guidance on when and when not to take a DNA sample.
The report, Nothing to hide, nothing to fear?, says that it was told by a retired senior police officer that it was routine for police to make arrests whenever they could so that DNA samples can be collected.
"It is now the norm to arrest offenders for everything if there is a power to do so … it is apparently understood by serving police officers that one of the reasons, if not the reason, for the change in practice is so that the DNA of the offender can be obtained," said that former officer's evidence to the HGC. "It matters not, of course, whether the arrest leads to no action, a caution or a charge, because the DNA is kept on the database anyway.”
The DNA database has been a source of controversy and legal action. The European Court of Human Rights told the UK that the practice of police forces in England and Wales of keeping the DNA of anyone arrested regardless of whether they were found guilty of a crime or even charged was a breach of their human rights.
It said that the "blanket and indiscriminate" collection of profiles was a "disproportionate interference with the applicants' right to respect for private life", as guaranteed by the European Convention on Human Rights.
The Government's initial response was to say that DNA records of innocent people could not be kept for longer than 12 years. It has since reduced that period to six years.
A different procedure exists in Scotland, where DNA samples can be taken but are deleted samples of those who are not convicted, except in the case of some sexual offences.
The HGC has said that the database itself was not created by Parliament or by the specific will of any Government, but has simply evolved. It should be the subject of parliamentary debate and should be controlled by primary legislation, it said in its report.
"The purpose of the database has altered over time and has never been stated in sufficiently clear terms," said its report. "The National DNA Database should be established in law through new primary legislation."
"The permitted uses of the records constituting the National DNA Database should be simply, unambiguously and explicitly defined in legislation, and any use of the database that falls outside those permitted uses should be made an offence subject to strict penalties … The legislation that establishes the National DNA Database should be accompanied by a full privacy impact assessment with advice from the Information Commissioner, so that these impacts can be considered when the legislation is debated openly in Parliament."
To counteract any actions by individual police officers who may be making arrests purely to collect DNA samples, the HGC said that guidance for officers should be published and their adherence to it monitored.
"We recommend that new guidance is given on when it is appropriate to take a DNA sample following arrest and to record a resulting DNA profile on the National DNA Database," it said. "Furthermore, we recommend that an independent panel reviews, at regular intervals, evidence relating to arrests and the taking of DNA samples, in order to ensure that (1) the guidance is sufficiently robust and (2) the guidance is being appropriately followed."
The report said that the UK's DNA database is the largest in the world, with five million records.
"DNA evidence plays a significant role in bringing criminals before the courts and securing convictions," said HGC Chair, Professor Jonathan Montgomery. "But it is not clear how far holding DNA profiles on a central database improves police investigations. We have to strike a proper balance between identifying offenders and protecting privacy, including that of innocent people – we should not compromise that privacy without good reason."
"There has been a steady 'function creep', allowing more and more people’s DNA to be kept, but it is not clear that this is matched by an improvement in securing convictions. There needs to be a regular review of the positive value we get from the database - its 'forensic utility'," he said.
The case which led to the European Court of Human Rights's ruling was that of Michael Marper, a man who was arrested and released without charge and who argued that the retention of his DNA was a breach of his human rights.