The European Court of Human Rights, in a landmark judgment delivered in December 2008, decided that the UK’s policy of retaining DNA samples and profiles of innocent people is indiscriminate and unlawful.

The decision is the end of a seven-year battle for justice by two Sheffield men.

In 2001, the Police and Criminal Evidence Act 1984 was amended so that police had the power to retain DNA and fingerprints of anyone who was charged with an offence, whether or not they were ultimately convicted.

Those acquitted of offences complained about this. It was argued that it was an unjustifiable breach of the right to respect for private life protected by article 8 of the European Convention on Human Rights.

S, a 12-year-old acquitted of attempted robbery, and Michael Marper, against whom domestic harassment charges were dropped, asked South Yorkshire Police to destroy their DNA but this was refused on the basis that, in all but exceptional cases, DNA and fingerprints would be retained.

Judicial review proceedings commenced with the home secretary an interested party. The government argued that retained samples were successfully being used to catch serious criminals who would otherwise escape justice.

The case travelled through the domestic courts, from the Divisional Court and through the Court of Appeal to the House of Lords. Ten domestic judges found against S and Marper. The reasons were always essentially the same. First, retention of DNA probably did not even engage the right to respect for private life. But even if there was a breach, it was so minor as to be easily justified by the inroads made in the fight against crime.

However, the judgments of Lord Justice Sedley and Baroness Hale, in the Court of Appeal and House of Lords respectively, held out some hope for the claimants. Sedley LJ thought that those completely free from the taint of suspicion might have a good case, while Baroness Hale found positively a breach of article 8(1). Lord Brown, meanwhile, completed his judgment by saying: ‘My concern is simply to indicate how very clear a case this seems to me to be. Indeed my only real problem now, following full investigation of the case with the assistance not only of the parties but from Liberty too, is in discerning any coherent basis on which the challenge can still be sustained.’

So how did such a comprehensive defeat in the UK courts become a unanimous victory in the Grand Chamber of the European court?

The European court took a wide view of the issues involved, looking at Council of Europe recommendations (and EU directives) on privacy and DNA use, comparative practices in other EU countries and the rather different system adopted in Scotland. The court found that the UK ‘is the only member state expressly to permit the systematic and indefinite retention of DNA samples of persons who have been acquitted’. The court also cited a report, published by the Nuffield Council on Bioethics in 2007, which raised a number of concerns about widespread DNA retention.

The court found that future concerns about the possible use of DNA samples could be taken into account in deciding whether there was an interference with private life. What is more, ‘given the nature and amount of personal information contained in… samples’, including the ethnic origin of a person, their retention per se amounted to an article 8(1) breach. The same was said about DNA profiles elicited from samples.

With regard to the justification for the breach (the article 8(2) argument), the court acknowledged the importance of the fight against crime and the assistance that retention of DNA samples could bring. The court recognised the UK’s argument that it was in the vanguard of the development of the use of DNA in the detection of crime (the UK’s DNA database is the largest in the world). But the ‘strong consensus’ of other states in limiting the use of DNA samples ‘narrows the margin of appreciation’ for the UK. Any state ‘claiming a pioneer role… bears special responsibility for striking the right balance’.

There was also criticism of government-produced figures on crimes cleared up as a result of DNA retention. The court noted that the majority of the government’s examples involved matching up suspects’ DNA with crime-scene stains, rather than using detained samples on the database. At the oral hearing, the government cited the murder of Sally Anne Bowman by Mark Dixie in 2005 and the murders of prostitutes by Suffolk serial killer Steve Wright to highlight the importance of DNA. However, these cases did not involve DNA samples retained from innocent people. In the Bowman case, DNA from the scene matched Dixie’s when he was later arrested for another assault. Wright had previously been convicted of theft and his DNA retained.

Ultimately, the court was ‘struck by the blanket and indiscriminate nature of the power of retention in England and Wales’. Any person charged with any offence of whatever gravity will have DNA retained for 100 years or until they die, with little chance of removal, and no independent review of the justification for retention. The court emphasised that the ‘stigmatisation’ of people not convicted of any offence, despite the presumption of innocence was of ‘particular concern’. It thought that only ‘weighty reasons’ could justify the different treatment of volunteers, whose samples are destroyed on request, and unconvicted persons. Of particular interest to the court was the fact that the same rules applied to juveniles (such as S) as to adults, despite the need to consider children differently under the criminal justice system to comply with the UN Convention on the Rights of the Child.

In summary, the retention of Marper’s and S’s DNA samples, profiles and fingerprints was a disproportionate interference with their right to respect for private life and a violation of article 8. The UK ‘has overstepped any acceptable margin of appreciation’ available to it, the court concluded.

The effect of the ruling will be global. This is the leading judgment on the issue of the expansion of biometric data, especially DNA databases. Several other countries and US states were expected to follow where the UK led, but will now have been stopped in their tracks. Of course, in the UK, the scope of retention has expanded even since 2001, to include now all those who are arrested even when there is no charge. It is estimated that 850,000 DNA samples of innocent people are on a DNA database that holds 4.5 million samples.

What will the government do? This was a case it did not want to lose and a large legal team was assembled to do battle in Strasbourg. It now has three months to explain what steps it will take to put in place provisions to comply with the judgment. In the cases of unconvicted people, the government and the police will need to consider, at the very least, the type of crime, the type of offender – especially if a juvenile – the strength of the evidence, the length of time that samples will be retained, and how any decision will be subject to independent review.

Detailed guidance might be issued to police forces, but ultimately it seems to us more likely than not that legislative change will be necessary. The Home Office has acknowledged that, as a result of the judgment, its plans to extend retention of DNA to low-level non-recordable offences and set up ‘short-term holding facilities’ in shopping centres are now dead in the water. The same must apply to any plan for a national DNA database of all UK citizens as well as ID cards that would include biometric data.

Whatever happens, the judgment has redrawn the parameters of state power and interference decidedly to the advantage of individual freedom. As one newspaper headline put it: ‘Big Brother humbled’.

Stephen Cragg is a barrister at Doughty Street Chambers in London. Peter Mahy is a partner at Howells, Sheffield. Both represented S and Marper in the Divisional Court, Court of Appeal, House of Lords and the Grand Chamber of the European Court of Human Rights.