British Law Enforcement Agencies Lobbied to Employ Biased Face Scanning Technology

Police forces across the UK effectively campaigned to deploy a face scanning system acknowledged as discriminatory against women, youths, and members of minority ethnic backgrounds, after complaining that a less biased version generated fewer investigative leads.

The Technology in Practice

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves matching a “probe image” of a person of interest against a repository of over 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office conceded last week that the system was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and women at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises 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.”

Known Issue

Official papers reveal that this bias has been recognized for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this decision was reversed the following month after forces complained that the modified technology was producing a lower number of “investigative leads”. Internal records show the stricter setting reduced the proportion of queries that yielded potential matches from over half to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these findings: “The testing identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the police records state: “This adjustment greatly lessens the effect of discrimination across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The papers add that police units complained that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the police race action plan, commented: “We observed very little consideration through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be taken without trained officers meticulously examining the output.”