The research, which examined how the new technology was being used by forces in West Yorkshire and Cumbria, found they were often recording crucial “signs of abuse” when officers first arrived on the scene of a domestic incident.
Interviews with 45 frontline officers, as well as police chiefs and prosecutors, found that they were able to film ongoing conflicts, physical injuries, disturbed furnishings or distressed witnesses, which could be used to ensure the perpetrators were charged and brought before the courts.
Stuart Lister, from the University’s Centre for Criminal Justice Studies, who led the research, said: “Officers told us that the videos had the potential to provide a more powerful picture about the impact of domestic abuse on victims – footage would show if people had been injured, were distressed or if the home had been damaged.”
One officer told the researchers: “I’ve seen a really good example of where a guy threw a bottle at his girlfriend and it slashed all the way down the back of her calf muscle and the paramedics were still there treating her – so it was an open, gaping wound. You can see the severity of the wound.
“What would have happened, we could say we saw a large gaping wound but we couldn’t do it justice when writing our case notes.
“So the body-worn cameras, in that sense, can capture evidence that is going to be lost or diminished.”
West Yorkshire Police has invested in 2,300 of the cameras, which are worn on police uniforms, and their use is now mandatory for all officers responding to domestic violence calls.
Interviewees reported that when cases get to court, some perpetrators pleaded guilty rather than contest the case because of the existence of the video evidence.
The study found that the cameras are increasingly being used to support so-called ‘victimless’ prosecutions, where the Crown Prosecution Service decides to charge an assailant even if the victim does not want to give evidence.
However, the roll-out of the cameras has not been without its problems, the study found. Both the West Yorkshire and Cumbria forces have pooled cameras, meaning officers have to pick one up at the beginning of each shift, and some said as a result they could find themselves with equipment that did not work.
There was also a concern that if footage showed abuse victims appearing more resilient than might be expected, this could harm the prosecution case.
The study added: “Further, police said victims sometimes either refuse to talk to them once they learn they are being filmed or insist the cameras be turned off.”
John Robins, Deputy Chief Constable of West Yorkshire Police, said body-worn cameras were now “part of routine policing” in West Yorkshire.
He said: “Most notably, they are greatly assisting our investigations into domestic abuse.
“In many cases the body-worn camera acts as an independent witness for victims, or gives confidence to victims, leading to more prosecutions and more early guilty pleas. However, body-worn cameras do not replace traditional investigative skills.
“They are not a replacement for good-quality investigators, but they certainly make us more efficient and effective in policing.”
Body-worn cameras are now being used by all four of Yorkshire’s police forces.
This week, North Yorkshire Police began issuing the kit to armed, Taser and response officers as well as custody staff.
In May, Humberside Police began a roll-out of cameras to more than 1,700 officers and staff.
And in March, South Yorkshire Police chiefs said they would be issuing armed officers with body-worn cameras and it remained an ‘ambition’ to secure them for officers responding to domestic violence incidents.
West Yorkshire Police has used the devices since piloting them in May 2016.