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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as biased against females, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This procedure entails matching a “probe image” of a person of interest against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This admission came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate discrimination in race and gender. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was more likely to produce false positives for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be raised to a point where the disparity was significantly reduced.

However, this directive was reversed the following month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the stricter setting cut the number of searches resulting in possible identifications from over half 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 found the system could produce incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The ministry commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of facial recognition technology. The minister for police 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 equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “We treat the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist police to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be taken without trained officers meticulously examining the results.”