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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against women, youths, and members of ethnic minority groups, following complaints that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This admission came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users tolerate biases in ethnicity and sex. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers show that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was had a higher probability to produce false positives for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches 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 modified technology was generating a lower number of “investigative leads”. NPCC documents show the stricter setting reduced the proportion of searches that yielded potential matches from over half to a just 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study discovered the system could generate incorrect matches for Black women almost 100 times more frequently than for white women at specific configurations.

The Home Office commented on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents further note that police units complained that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool 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: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

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

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be pursued without trained officers meticulously examining the output.”