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Police forces across the UK effectively campaigned to deploy a facial recognition system known to be discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This process entails matching a “probe image” of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

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

Known Issue

Internal documents reveal that this bias has been recognized 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 algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the disparity was significantly reduced.

However, this directive was reversed the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. Internal records indicate the higher threshold cut the proportion of searches that yielded potential matches from 56% to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the recent independent review discovered the system could produce incorrect matches for women of Black heritage almost 100 times more often than for white women at certain settings.

The ministry stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the police records state: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The documents further note that forces argued that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology 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 national policing equality strategy, said: “We observed very little consideration in race action plan meetings of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made via the race action plan are not being translated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “We treat the conclusions of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist 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 pursued without specialist personnel carefully reviewing the results.”