🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against females, youths, and members of ethnic minority groups, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces use the national police database to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was flawed. This acknowledgment followed a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at much greater frequency than white men. The ministry stated it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the system's bias in September 2024. The government-ordered NPL review concluded the system was more likely to suggest incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be increased to a level where the bias was significantly reduced.

However, this decision was reversed the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of searches resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study discovered the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these findings: “The testing identified that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of bias across protected characteristics of race, age and sex but had a substantially detrimental effect on police efficiency”. The papers add that police units complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination policing has made via the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to strict national standards, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”