The National DNA Database contains the profiles of 1.1 million children, including 337,000 under 16s, it has emerged.
The Metropolitan Police has added the largest number of profiles, adding the data of 117,000 boys and 33,000 girls, according to a parliamentary written answer.
The news has further stoked the fires of a row over storage of the children’s data, when many of them have not been convicted of a crime.
Some 88 percent of the children were charged, convicted or received a final warning, said the National Policing Improvement Agency, which runs the database, according to the Guardian newspaper.
But Action on Rights for Children and Genewatch, two pressure groups, produced an estimate that 100,000 innocent children remained on the database, the paper reported.
Three weeks ago, the Lords Constitution Committee lambasted the government for its continued creation of databases on citizens, which it said “risks undermining the fundamental relationship between the state and citizens, which is the cornerstone of democracy".
Commenting on the committee's findings, the Information Commissioner's Office also highlighted "the dangers of sleepwalking into a surveillance society".
Liberal Democrats home affairs spokesperson Chris Huhne said: “It is unacceptable to keep the DNA of children on record in perpetuity for the most minor of offences. Unless convicted of a sexual or violent offence, under-16s should not have their DNA stored on the database."