🔗 Share this article

Police forces across the UK effectively campaigned to use a facial recognition system known to be discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office admitted last week that the technology was biased. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users accept discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

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

Police bosses were notified of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to produce false positives for photos of females, Black people, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be raised to a level where the disparity was significantly reduced.

However, this directive was reversed the next month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of queries resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the recent independent review found the system could produce incorrect matches for Black women nearly a hundred times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing found that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the impact of bias across protected characteristics 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 returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed scant consideration through equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made via the equality initiative are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

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

Official Statement

A government representative said: “We treat the findings of the study seriously and we have already taken action. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist police to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the results.”