Every police force in England and Wales will be equipped with mobile fingerprint scanners to check the identity of suspects in the street.

Up to 3,000 devices, the size of a mobile phone, will enable officers on patrol to cross-reference prints with national records.

Senior officers claimed the scheme would speed up criminal inquiries, bring more people to justice and save thousands of hours of police time.

But fears have arisen the technology could contribute to the so-called "surveillance state" and encourage random searches.

Police said scanned fingerprints would only be stored for a short time while they were checked and would not be added to any databases.

The National Police Improvement Agency (NPIA) said the contract was worth £9 million over three years.

A limited trial of 330 mobile fingerprint devices, in which heavier machines were carried by motorway patrols, started in 2006 and eventually involved 28 forces.

The pilot, known as Operation Lantern, showed officers saved at least 30 minutes every time they used a machine.

The technology was also used to identify murder victims and people left unconscious or incapable as a result of road crashes.

The device works by electronically scanning the subject's index fingers. The results are then encrypted and sent to a central database.

The images are then cross-referenced against the national fingerprint collection of 8.3 million prints. Each search takes less than two minutes.

Chief Constable Peter Neyroud, of the NPIA, said: "From hours to minutes, advances in fingerprinting technology are helping the police to identify one person from many.

"Identification is crucial to police investigations and giving officers the ability to do this on the spot within minutes is giving them more time to spend working in their communities, helping to fight crime, bringing more offenders to justice and better protecting the public."

In a report published last year, campaign group Liberty said the devices could encourage officers to usurp their powers to request fingerprints.

The organisation said it had "very real concerns" about the move and said there needed to be more debate over use of the machines.

Original Source - http://www.independent.co.uk/news/uk/crime/police-to-be-equipped-with-mobile-fingerprint-scanners-1916123.html