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Police forces across the United Kingdom successfully lobbied to use a face scanning system acknowledged as biased against females, youths, and individuals from ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

UK forces use the national police database to conduct searches using historical face recognition. This procedure involves comparing a reference photograph of a person of interest against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment came after a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“This raises the issue of whether this technology only becomes effective if users tolerate biases in race and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce false positives for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be raised to a level where the disparity was significantly reduced.

However, this directive was overturned the next month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents show the higher threshold reduced the proportion of queries that yielded possible identifications from 56% to a just under 15%.

Severe Disparities

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

The ministry stated on these results: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments policing has made through the race action plan are not being translated into broader operations. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the conclusions of the study with utmost gravity 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 gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no further action would be taken without specialist personnel meticulously examining the results.”