Britain is taking its surveillance to a new level — strapping video cameras to police officers' heads, the government said Friday.

Advocates say the devices will cut down on paperwork and supply the nation's justice system with footage of victims, witnesses and suspects.

Minister for Security Tony McNulty said judges and jurors trying a case would be able to "see and hear the incident through the eyes and ears of the officer at the scene."

The Home Office has allocated of $6 million to fund the devices for Britain's 42 police forces — enough to buy more than 2,000 cameras.

Police already use handheld cameras to monitor crowded events and their head-mounted counterparts, worn around the ear or clipped on to a helmet, have been used on a trial basis by the police in Plymouth, in southwest England, since 2005. Similar cameras are used by security guards at sports venues to hunt for soccer hooligans.

Britain is not the first country to use such devices — versions of which have been tested in Copenhagen, Denmark. But the national rollout will tighten Britain's web of video surveillance, already the most extensive in the world. The country is watched over by a network of some 4 million closed-circuit cameras, and civil liberties campaigners complain that the average Briton is recorded as many as 300 times a day.

In a report on the Plymouth pilot project published by the Home Office on Thursday, policemen praised the head-held cameras for deterring bad behavior and providing excellent evidence in court.

They said rowdy youths quickly calmed when they realized they were being filmed, and those arrested for drunkenness at night seldom challenged police when shown videos of their behavior in the morning. Prosecutors credited the cameras with emboldening victims of domestic violence to press charges against their partners, although the director of Rights of Women, Ranjit Kaur, said she has not been convinced the footage alone could help secure a conviction.

The Association of Chief Police Officers, an independent body of senior police officials in England, Wales and Northern Ireland, gave the devices a cautious welcome, saying courts might someday expect everything police said to be backed by video evidence.

"The introduction of personal digital recording equipment for police officers and staff brings benefits and risks," the association said in a statement. "We need to guard against creating an expectation that all police activity ought to be supported by the use of digital recording technology."

But civil rights group Liberty praised the guidelines included in the Home Office report. Spokeswoman Jen Corlew noted that police were asked to inform members of the public they were being recorded and that the footage not being used in an investigation had to be erased within a month of its creation.

The Home Office said the cameras — which have enough memory to hold 24 hours of video — were not intended to record continuously. Officers would turn the devices on and off at their discretion, speaking into the camera after turning it on to explain where, when and why they were starting it. A second explanation was required before turning the device off.

The report also cautioned against taking extraneous video when entering private homes, and said officers should turn cameras off during strip searches. But it also threatened disciplinary action against officers who deliberately masked the camera's view or deleted video from the camera's memory.

The Home Office said it was exploring other uses for the devices, including fitting them with the ability to send video live to a command center, or special license-plate recognition software which would enable police to identify stolen or suspicious vehicles just by looking at them.