I am glad that Tory MP Damian Green's DNA has been taken off the government's database. It was concerning. The police raid on his office was wrong in the first place. So why should an innocent man have his DNA kept in this way?

But I am even more concerned about the hundreds of thousands of other innocent people with their DNA on the government database, particularly children.

Professor Sir Alec Jeffreys, the scientist who discovered the significance of DNA, made it clear years ago that he thought it was wrong for the government to keep the DNA of innocent people. He said: "I'm totally opposed ... It's discriminating, inconsistent with privacy laws and an example of ad hoc sloppy thinking."

Dame Helena Kennedy, when she was chair of the human genetics commission, warned that this would create a class of people who were permanently under suspicion, even though they had never been convicted of any wrongdoing. "Being on a database of potential offenders which might be regularly trawled by the police means that one is on a list of suspects and that surely very subtly alters the way in which the state sees, and we see, our fellow citizens."

The European court of human rights also ruled this year that the "blanket and indiscriminate" retention of suspects' DNA was unlawful.

There is a clear racial disparity in those people who have their DNA held. In particular, one in four black children over the age of 10 have their DNA on the database. I dealt with the case of a 14-year-old black girl who happened to be a passenger in a car which was stopped by the police. She had her DNA taken without her parents being present or their permission sought. The car was not stolen and the driver had committed no crime. But it took months of argument before the police agree to remove her DNA. It seems that for the police, if you are a young black person of any gender, you are guilty until proved innocent and permanently under suspicion.

DNA evidence has undoubtedly been useful in clearing up crimes of sexual violence and assault. But the government needs to adopt much stricter guidelines in retaining the DNA of innocent people.

So I am pleased to be working with Liberty in holding a series of special advice clinics in Hackney to advise innocent young people how they can remove their DNA from the government's database. If they can do it for Damian Green MP, they can do it for my young constituents.