By Rory Carroll, Nov. 4, 2013, Theguardian.com

The occupant was said to be violent, so officer Carlos Ramirez approached the apartment warily. A dank smell wafted from inside. Ramirez bristled with body armour, radio, gun and Taser, but before knocking on the door he adjusted just one piece of equipment: a tiny camera on his collar.

A tubby, barefoot man with broken teeth and wild eyes opened the door. He appeared to be high. Ramirez questioned him about allegedly beating and evicting his stepson, a mentally disabled teenager. The man shifted from foot to foot and babbled about death threats.

The encounter, tense but polite, ended inconclusively, a routine police foray into family dysfunction – except for the fact it was all recorded. As he returned to his patrol car and next assignment, Ramirez tapped an app on his phone and uploaded the video. "Somewhere down the line something could happen and what that guy said, his demeanour, could be evidence."

Rialto, a small, working-class city that bakes in the San Bernardino foothills outside Los Angeles, appeared in the films Transformers and The Hangover. Among law enforcers, however, it is becoming better known for pioneering the use of body cameras on police officers.

Over the past year all 70 of its uniformed officers have been kitted out with the oblong devices, about the size of stubby cigars, and the results have emboldened police forces elsewhere in the US and in the UK to follow suit.

The College of Policing recently announced plans for large-scale trials of body-worn video in England and Wales, saying Rialto's experiment showed big drops in the use of force and in public complaints against officers. David Davis, a former shadow home secretary, has backed the idea. It follows "plebgate's denting of public trust.

Rialto has also become an example for US forces since a federal judge in New York praised its initiative.

"I think we've opened some eyes in the law enforcement world. We've shown the potential," said Tony Farrar, Rialto's police chief. "It's catching on."

Body-worn cameras are not new. Devon and Cornwall police launched a pilot scheme in 2006 and forces in Strathclyde, Hampshire and the Isle of Wight, among others, have also experimented.