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

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process entails comparing a “probe image” of a person of interest against a database of over 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This admission came after a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users accept biases in race and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a level where the disparity was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was generating a lower number of “investigative leads”. NPCC documents show the higher threshold cut the proportion of searches resulting in possible identifications from 56% to a just under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest independent review discovered the system could generate false positives for Black women almost 100 times more often than for Caucasian women at specific configurations.

The ministry commented on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant discussion through race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson stated: “We takes the conclusions of the study seriously and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”