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Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a “probe image” of a suspect against a database of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission followed 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 stated it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 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 next month after forces complained that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the higher threshold cut the number of searches resulting in possible identifications from 56% to a mere under 15%.

Severe Disparities

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

The Home Office commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and sex but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed very little discussion through race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has undertaken through the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“All deployment of this technology must meet strict national standards, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A government representative stated: “We treat the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in every step of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”