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Police forces across the UK effectively campaigned to deploy a facial recognition system acknowledged as biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

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

“It prompts the issue of whether this technology only becomes useful if users tolerate biases in race and sex. Operational ease is a weak argument for overriding basic freedoms.”

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 initial decision that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest 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 accuracy setting required for potential matches be increased to a point where the disparity was greatly diminished.

However, this directive was overturned the next month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of queries resulting in possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the recent independent review found the system could produce false positives for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The Home Office stated on these results: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The papers add that police units complained that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was scant consideration through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo further assessment.

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