Police in Suffolk have defended the rising number of cases where DNA samples are taken from children - including many of primary school age.

The figures, revealed by the Howard League for Penal Reform, show that hundreds of children aged under 17 are among those who have had their DNA recorded.

The charity claims many of the children required to give a sample will not have been charged with a criminal offence.

Under current rules, police can retain indefinitely the DNA of anyone they arrest for a recordable offence - although a new law, imposing tighter restrictions on DNA retention, is expected to come into force later this year.

The new rules have been welcomed by the charity, which feels in many cases taking DNA samples from children is unnecessary.

But last night, Suffolk police defended the practice, saying it had an important role to play in the detection of crimes - and could also exonerate “many innocent people”.

A Freedom of Information request by the penal reform charity found that Suffolk officers took swabs from 614 boys and girls aged 17 or under during 2011 - and increase from 586 the previous year.

They included 18 primary school-age children – two 10-year-olds and 16 children aged 11. Suffolk was one of only three forces in the country where the sample numbers increased between the two years.

In Essex, samples from 1,693 children were taken in 2011, including 12 ten-year olds and 44 11 year-olds. That was a fall from 2,320 in 2010.

The Howard League’s chief executive Frances Crook said: “When public money is tight and police forces are shrinking, it is disappointing to see valuable crime-fighting resources being wasted on taking DNA samples from innocent children while serious offences go undetected.

“Children who get into trouble with the police are usually just up to mischief. Treating so many like hardened criminals by taking their DNA seems excessive.

“We welcome the government’s decision to stop storing innocent people’s DNA indefinitely, but it remains unclear how this will affect the number of children having their DNA taken needlessly.”

However, police officers say taking DNA samples is an important weapon in fighting crime.

A Suffolk Constabulary spokesman said: “DNA evidence is a robust and vital technique for police in the detection of crimes. It has been used to not only convict many criminals but also to exonerate many innocent people, including young people, and is a valuable tool in investigating crime.

“There is legislation governing how the police can take and retain DNA evidence. The service will continue to take samples and retain profiles appropriately, in accordance with the law, so that we can identify criminals and keep the public safe.”

Across England and Wales, police took swabs from almost 54,000 boys and girls aged 17 or under during 2011. About 30 per cent of the child DNA samples taken by police come from girls.