By JAMES SLACK

Last updated at 07:35 23 May 2007

The number of innocent children placed on the Government's vast DNA database for life has quadrupled in the past year to more than 100,000, it has emerged.

The astonishing increase, which follows a controversial change to the law, was described by opposition MPs as an "extremely sinister development".

It will fuel concerns that police are targeting for arrest youngsters who have done nothing wrong, simply to get their hands on their DNA.

Terri Dowty, director of the pressure group Action on Rights for Children, said: "These are shocking statistics. These children will be on the database for the rest of their lives.

"Whenever their DNA is found at a crime scene, they will have to be prepared to justify themselves. We are turning thousands of innocent children into lifelong suspects."

The revelation a year ago that the details of 24,000 innocent youngsters had been stored on the DNA database brought widespread alarm.

But research by Action on Rights for Children and the pressure group GeneWatch UK, using Home Office figures, reveals that - far from being deterred - police have accelerated sharply the rate at which they are gathering samples from children.

In the past 12 months, the samples of 81,000 children convicted of no crime have been added to the database, which can be checked against any crime scene. It takes the total to 105,000.

Since April 2004, anyone aged ten or above who is arrested in England or Wales can have their DNA and fingerprints taken without their consent, or that of their parents.

The DNA samples are all kept permanently. The computerised DNA profiles are also kept permanently on the DNA database, even if the person arrested is never charged or is acquitted.

The law was not fully implemented in 2004/05 but last year it was introduced across the country. These figures reveal for the first time the astonishing impact of the move.

Around 80,000 innocent children are likely to be added to the database every 12 months, as that is the average number of children arrested for the first time each year but never convicted. Parents can appeal to have their child's DNA removed but this is at the discretion of chief constables.

Very few samples are removed, with the rest stored for life.

Police say those who have had their DNA taken include two schoolgirls charged with criminal damage after drawing chalk on a pavement and a child in Kent who removed a slice of cucumber from a tuna mayonnaise sandwich and threw it at another youngster.

Shadow Home Secretary David Davis said: "This is an extremely sinister development. One hundred thousand innocent children have their DNA data stored by stealth. This is a big move towards the end of the presumption of innocence for our youth."

Dr Helen Wallace, director of GeneWatch UK, said: "Anyone with access to the DNA database can use these children's DNA profiles to trace where they have been, or who they are related to.

"Do we really trust the Home Office not to misuse this information and to safeguard it from others who may want to infiltrate the system?"

The number of innocent people on the database, including the 105,000 children, is one million - 25 per cent of the four million who have their DNA stored.

It is the world's largest database and has raised concern that Britain is lurching towards a "surveillance society".

Criminologists have warned that, in order to make policing simpler, officers are targeting for arrest those they see as potential troublemakers. By making arrests for a minor offence such as criminal damage, they can take the DNA of a group of youngsters at the same time.

No charges need to be made, but the samples can be stored.

A Home Office spokesman said last night: "Taking a DNA sample and fingerprints from those arrested for a recordable offence and detained in a police station, including juveniles aged ten to 17, is now part of the normal process within a police custody suite.

"Those who are innocent have nothing to fear from providing a sample and retaining this evidence is no different to recording other forms of information such as photographs and witness statements."