If Britain’s most senior police forensics expert has his way, primary school children could be required to submit DNA samples to be kept on file for all time.

Gary Pugh, director of forensic sciences at Scotland Yard, wants to collect and store DNA samples from any kids who exhibit behaviour indicating they may become criminals in later life. Civil liberty groups condemned his comments, likening them to an excerpt from a science fiction novel.

Pugh says a debate is needed to determine how far Britain should go in identifying potential offenders, given that some experts believe it is possible to identify future offending traits in children as young as five.

“If we have a primary means of identifying people before they offend, then in the long-term the benefits of targeting younger people are extremely large,” said Pugh. “You could argue the younger, the better. Criminologists say some people will grow out of crime; others won’t. We have to find who are possibly going to be the biggest threat to society.”

Pugh admits the deeply controversial suggestion raises issues of parental consent, potential stigmatisation and the role of teachers in identifying future offenders, but said society needed an open, mature discussion on how best to tackle crime before it took place. Britain currently maintains the largest DNA database in Europe, with 4.5 million genetic samples on file.

Pugh says the idea of universal sampling, forcing everyone to give a DNA sample is prohibitively expensive and poses a logistical nightmare.

Pugh’s call for the government to consider options such as placing primary school children who have not been arrested on the database is supported by elements of criminological theory.

A well-established pattern of offending involves relatively trivial offences escalating to more serious crimes. Senior Scotland Yard criminologists are understood to be confident that techniques are able to identify future offenders.

Shami Chakrabarti, from the civil rights group Liberty, denounced the scheme.

“Whichever bright spark thought this one up should go back to the business of policing or the pastime of science fiction novels,” she said. “The British public is highly respectful of the police and open even to eccentric debate, but playing politics with our innocent kids is a step too far.”

Pugh, though, believes that measures to identify criminals early would save the economy huge sums since violent crime alone costs the UK £13 billion a year.

He said the British public needed to move away from regarding anyone on the DNA database as a criminal and accepted it was an emotional issue.

“Fingerprints, somehow, are far less contentious,” he said. “We have children giving their fingerprints when they are borrowing books from a library.”