The Government's illiberal juggernaut smashed into a brick wall yesterday. The European Court of Human Rights has ruled, in a unanimous judgment, that South Yorkshire Police's retention of the DNA of two men who had committed no crime was not only a breach of their civil liberties, but also fundamentally undemocratic.

The implications of this judgment will resound across Britain. The 2001 Criminal Justice and Police Act permitted the police to take and retain DNA samples from anyone they arrested, regardless of whether their target was eventually charged or convicted of a crime. It is not a power the police have been shy in exercising. The national DNA database now contains the details of 4.5 million people, making it the largest of its kind in the world. A fifth of those included do not have criminal records. The Strasbourg judgment means that some 850,000 records will have to be wiped.

The court also noted yesterday that it was, "struck by the blanket and indiscriminate nature of the power of retention in England and Wales". This is an indictment, not only of the Government, but Parliament which passed the legislation giving the police these sweeping powers. Our MPs and peers were asleep on the job when they allowed this wretched piece of legislation through.

The Government, naturally, is showing no signs of contrition. The Home Secretary, Jacqui Smith, yesterday remarked that she was "disappointed" at the Strasbourg ruling, arguing that, "DNA and fingerprinting is vital to the fight against crime, providing the police with more than 3,500 matches a month". This response reeks of intellectual dishonesty. The critics of the present law have not called for the destruction of the DNA database, merely the wiping of the samples of innocent people. This is what happens in Scotland. There is no earthly reason it should not be the case across the rest of Britain too.

It does not take any great insight to discover the Government's real agenda. Ministers have claimed in the past that DNA profiles from those not charged or convicted are sometimes linked to later offences; that the bigger the database the more chance of catching criminals. But by this logic, the Government ought to be asking the entire population to submit DNA samples to their local police station. They know this would never be acceptable to the country, so they are instead growing the database by stealth. Thankfully, the European court has called time on this underhand project.

Yet this is simply one victory in a much larger war against a Government which refuses to recognise the limits of the state's role in our private lives. Ministers show no sign of relenting in their efforts to foist costly and intrusive ID cards on us. The Immigration and Citizenship Bill in the Queen's Speech this week would allow state officials the power to demand proof of identity from the public on a whim. And then there are proposals in the new Coroners and Justice Bill to give public bodies the unrestricted ability to transfer our personal information between themselves.

This Government has proved itself again and again to lack any understanding of either the acceptable boundaries of official intervention in our personal lives or the overwhelming necessity to safeguard the public's private data. With yesterday's judgment the juggernaut has been slowed, but not stopped. The campaign to protect our civil liberties goes on.