Police in London.Photograph:Max/Flickr.

DNA samples have been taken from children in Camden, north London, at therate of one a day, new figures have revealed.

Home Office guidelines allow police to take DNA from persons of any age who are arrested for a recordable offence. Jo Shaw, Liberal Democrat parliamentarycampaigner for Holborn and St Pancras, submitted a Freedom of Informationrequest to the Metropolitan police to discover how the DNA database was affecting children.

She was shocked by the figures that revealed that 386 DNA samples were taken from children in Camden in 2008. One hundred and eighty-six DNA samples were taken in the first five months of this year alone.

“I didn’t think that it would be as high as it was,” said Jo Shaw. Ms Shawasked for the figures for Camden, her home constituency, but believes thatthe authorities in other parts of the country maybe adding similarly high numbers of children to the DNA database.

“I would be astonished if it was only happening in Camden. It’s almostcertainly happening on a national level in all the police authorities, andcertainly across London,” said Ms Shaw.

She said that the figures refer to the number of samples taken, not thenumber of children. Some children could have given samples more than once.

The Metropolitan Police responded to the figures saying that they werefollowing Home Office guidelines. Chief Inspector Sean Wilson, of Camdenpolice, said: "The DNA database is a nationwide one. Legislation governing the recording and retention of DNA is adhered to by Camden police." However, a number of children now on the DNA database were neither chargednor convicted of any crime when they gave a DNA sample to police. “Myconcern,” said Ms Shaw, “Is that this policy is a breach of our justice system that states that you are innocent until proven guilty.”

The next step in Ms Shaw’s FOI requests is to find out the number of children under 10 who have had samples taken. Her Freedom of Information request for the figures was previously declined on the basis that the data for offenders under 10 is not retained because they are under the age of criminal responsibility.

Ms Shaw was elected last Friday to the council of Liberty , the cross-party organisation that campaigns for human rights and civilliberties. Ms Shaw wants to encourage more debate regarding what personalinformation is kept and how it is used. “It is starting to happen,” she said, “The amount of information kept about each individual should beproportional to its usefulness in each individual case.