Police should look at using artificial intelligence to help cope with the scale of information involved in investigations and avoid the kinds of mistakes that have led to a string of collapsed rape trials, a senior police chief said on Wednesday.
Sara Thornton, the chair of the National Police Chiefs’ Council, said the volume of data held by individuals had massively increased the number of potential lines of enquiry that officers must pursue to understand a case.
In recent months, several rape prosecutions have been dropped after it emerged that police had failed to hand over evidence that undermined their cases. Since then, the Crown Prosecution Service has announced a review of all current rape cases and Nick Ephgrave, the NPCC’s lead on criminal justice, has admitted that police have a “cultural problem” with disclosure.
The attorney general’s guidelines on disclosure say that police have a duty to pursue all reasonable lines of investigation, leading both towards and away from a conviction, Thornton said. Raising the prospect that more challenges may emerge in the future, she said that the problem was linked to violent crime, but that “in the first instance” issues had emerged around sexual offences.
“What we are really challenged by is the volume of data which all of us hold in 2018, and therefore the potential for many, many more reasonable lines of enquiry than was ever the case. I’m not just talking about twice as many ... the numbers that we’re talking about are really significant.”
Thornton said that suspects and complainants should be asked at the outset of an investigation whether there might be any evidence on their phones or digital footprints which are relevant. But, with tight resources, the ultimate answer lay in technology.
“I think the challenge for us is how we can use technology more, beyond search terms. So how can you use ... machine learning, artificial intelligence, whatever phrase you want to use, to get clever tech to help us to do this?”
Such methods were already in use in civil cases, Thornton said, and the CPS has now set up a group to look at how it could be employed in criminal trials. “Because, in a way, it’s technology that’s causing us the big challenge, technology has got to be part of the answer, so that’s what we are trying to do.”
Thornton’s comments came ahead of an NPCC briefing on knife crime, where the organisation’s lead on the issue announced a nationwide week of action from Monday. Duncan Ball, a deputy assistant commissioner in the Metropolitan police, said the operation would include knife sweeps, targeted stop and search, and test purchases.
Anecdotal reports from officers in units that focus on gang crime, such as the Met’s Trident Command, suggested that a cut in the numbers of stop and search had given youngsters the impression they were less likely to be searched, he said.
Ball also said that he would be travelling to Scotland, where authorities have taken a “public health approach” to knife crime that has led to a dramatic fall in the number of fatal stabbings.
“Clearly, it’s been successful in Scotland,” Ball said. “One of the interesting things I think – and I obviously completely support the comments of the commissioner previously made in that it sort of takes a more holistic, more of a wide-system approach to how we’re looking at it – is identifying how that can be transferred.”
However, different forces with different needs would need to apply the principles in different ways, Ball said, adding that he would guard against a “one-size-fits-all approach”.
“I think the other challenge within that [is that it’s] clearly not just a policing issue, it’s health, education, everything else that’s involved in it. I think, again, there’s a strong role for the Home Office in providing the broader strategy at the moment in terms of how the intervention, the health bit, is included.”