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Police forces across the UK effectively campaigned to use a facial recognition system acknowledged as discriminatory against females, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This admission came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in ethnicity and sex. Convenience is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were informed 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 images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a level where the disparity was greatly diminished.

However, this directive was overturned the next 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 number of queries resulting in possible identifications from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study found the system could produce false positives for Black women almost 100 times more often than for white women at certain settings.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The papers add that forces complained that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the pledges to combat discrimination the police has made via the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We treat the findings of the report with utmost gravity and we have implemented changes. A new algorithm 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 protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”