An increase in the use of body cameras by police has led to a huge drop in complaints made against officers, research shows.
A study by the University of Cambridge found a 93% decrease in complaints made against officers clearly wearing the cameras, which record what happens during police incidents, compared to the previous year.
Researchers said the result "assumes that BWCs (body-worn cameras) reduce officer non-compliance with procedures, improve suspects' demeanour, or both".
The study, which involved West Midlands Police, West Yorkshire Police, Cambridgeshire Constabulary and the Police Service of Northern Ireland, suggests that the "observer effect" of the cameras influences the behaviour of both officers and citizens.
Dr Barak Ariel, leading the research, said that the results suggested wide use of BWCs could reduce violence conflicts with officers and mark a significant cultural change in policing.
His report stated: "Cooling-down potentially volatile police-public encounters to the point where official grievances against the police have virtually vanished may well lead to the conclusion that the use of BWCs indeed signals a profound sea change in modern policing."
But the study comes only a few weeks after it was revealed that there is a "complete lack of consistency" in the use of BWCs by officers armed with Tasers.
A survey by the Press Association of the UK's 45 territorial forces showed that many have not completed a full roll-out of the equipment among staff, and at least one has said it has no current plan to adopt the cameras.
The issue was highlighted following the death of former football star Dalian Atkinson after he was Tasered in Telford, Shropshire, on August 15.
But the College of Policing said there was "no specific guidance" for issuing armed officers in the UK with bodycams, although it did issue advice on usage in 2014.
Both the Home Office and the National Police Chiefs' Council (NPCC) have said the use of BWCs is an "operational" decision for each force.
During the Cambridge study, conducted across seven sites, researchers found that the number of complaints lodged against officers dropped from 1,539 (which equates to 1.2 per officer) to 113 in 12 months.
But the report pointed out that these results give no evidence of other areas in policing and that the BWCs do not necessarily have a long-term effect on general police "legitimacy".
It said: "Even if BWCs can lead to perfectly executed police procedures ... what happens before or after the encounter might still be perceived as unfair, racist, unprofessional, or malicious."