🔗 Share this article

Police forces across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a suspect against a database of more than 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate discrimination in race and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a point where the disparity was significantly reduced.

However, this directive was reversed the following month following complaints from police that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting reduced the proportion of searches that yielded possible identifications from over half to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the latest NPL study found the system could produce false positives for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “The change greatly lessens the effect of bias across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The papers further note that forces complained that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments policing has made through the equality initiative are failing to be integrated into broader operations. Our reports have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the findings of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be taken without trained officers meticulously examining the results.”