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Law enforcement agencies across the UK successfully lobbied to deploy a face scanning system acknowledged as biased against females, youths, and members of minority ethnic backgrounds, after complaining that a less biased version generated fewer investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women 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 effective if users accept biases in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Known Issue

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a point where the disparity was greatly diminished.

However, this directive was reversed the next month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the stricter setting reduced the number of searches resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the latest NPL study discovered the system could produce incorrect matches for Black women nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The documents further note that police units argued that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

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

“These revelations show once again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Home Office Response

A government representative stated: “The Home Office takes the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“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 each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”