One rule for MPs?
You may remember the arrest of Damian Green, the shadow immigration minister, as part of an investigation into leaks from the Home Office.
Well although he was never charged with anything, like many thousands of others in England, Wales and Northern Ireland, his DNA details were kept by the police. Tonight he's told the BBC that his details are to be erased, after appeals from his solicitor.
Yet for many others, never convicted of a crime, having your personal profile removed from the giant DNA database proves nearly impossible.
We've spoken to someone whose 18-month legal battle to get his name removed has so far failed, for tonight's Ten O'Clock News.
Mr Green is now calling for other records to be expunged and says, if in government, the Conservatives would follow the model of Scotland.
There, out of those arrested but not convicted, only those questioned about sexual or violent offences have their DNA stored.
The Home Office has already been told by the European Court that keeping the DNA of anyone who is arrested indefinitely is illegal. That was back in December. But despite a consultation on what to do next, don't expect any changes in the guidelines soon.
A letter passed to me, written to chief constables by the Association of Chief Police Officers, says the new guidelines won't come into effect until 2010.
So in the meantime, they've been told to carry on as normal.
As the Home Office told me, clearly, DNA can be a critical tool for detectives. But after Damian Green's experience, the Conservatives aren't likely to let this drop.