THOUSANDS of children - some as young as 10 - are having their DNA stored on police computers.

The total number of under-18s on the database has more than tripled in the last three years from 10,425 in 2011 to 35,224 in the past year, according to new figures.

And 251 of the DNA profiles currently stored by police are from youngsters aged 13 and under, including two 10-year-olds.

Politicians and campaign groups yesterday voiced fears about the criminalisation of young children. Many of those added to the database have not committed any crime, as swabs are routinely taken when a suspect is arrested.

Scottish LibDems justice spokeswoman Alison McInnes MSP described the sharp increase as "sobering" and called for increased regulation of DNA retention.

She said: "DNA evidence has played a vital role in bringing many criminals to justice. But the collection and retention of DNA must be properly regulated.

"The fact that Police Scotland appear to be holding DNA records for children under the age of criminal responsibility is a particular concern. Ten-year-olds are not hardened criminals. They are children. If there are good reasons for keeping children's DNA on record at a time when overall crime is falling then we need to hear them."

The youngest child on the database is a 10-year-old who was arrested in Grampian, but DNA samples have been taken from those as young as eight previously.

Chief Executive of charity Children 1st, Alison Todd, said it was "concerning" to see the very young being labelled as criminals.

She said: "In Scotland, we have a history of looking at 'the needs not deeds' of children.

"Children 1st does not believe it is appropriate or necessary to retain any child's DNA or fingerprints for any length of time. Children have a right to be treated as children, with the right to special protection for their liberty and welfare. It is particularly concerning to see children who are very young being added to the database and effectively labelled as potential criminals. Children who offend are still developing and much more unlikely than adults to re-offend if they are given support to change problem behaviour and address any underlying causes. It is important to strike a balance between protecting the rights of the child and promoting effective law enforcement."

A total of 313,425 DNA profiles are held on the DNA database - about one in 17 of the population.

It was set up in 1996 and when it became fully independent of the UK-wide version in 2002, it held DNA from 123,115 individuals. The oldest person on the database is an 101-year-old who was arrested in Forth Valley eight years ago.

Clare Morgan, Head of National Systems Support for Police Scotland, said the single force was committed to keeping people safe. "DNA is a vital tool in the evidence gathered which can ultimately lead to the conviction of those who have committed crimes," she said. "When DNA is gathered it is stored and held within strict rules, guidelines and policies.

"Samples are added and removed regularly to and from the database depending on the offence involved in accordance with relevant legislation such as the Criminal Justice and Licensing (Scotland) Act 2010."

A Scottish Government spokesman said: "Responsibility for taking DNA lies with the police in the first instance. Scotland's DNA retention system has been widely praised for striking the right balance between protecting the public and protecting the rights of the individual and has been highlighted as a good model by the European Court of Human Rights."