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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as biased against females, young people, and individuals from minority ethnic backgrounds, following complaints that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to carry out searches using historical face recognition. This process entails comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to find potential matches.

Admitted Bias

The Home Office conceded last week that the system was flawed. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry stated it “had acted on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate discrimination in ethnicity and gender. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was overturned the following month following complaints from police that the modified technology was producing a lower number of “investigative leads”. Internal records show the stricter setting cut the proportion of queries resulting in potential matches from 56% to a just under 15%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, 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 certain settings.

The ministry stated on these findings: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's accuracy setting, the police records state: “This adjustment greatly lessens the impact of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units complained that “a once effective tactic now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to expand the use of biometric scanning systems. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion through race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into broader operations. Our reports have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be pursued without trained officers meticulously examining the output.”