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Police forces across the UK effectively campaigned to deploy a facial recognition system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated fewer potential suspects.

How the System Works

British police utilize the national police database to conduct retrospective facial recognition searches. This process involves 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 system was biased. This acknowledgment came after a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and sex. Convenience is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

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

However, this decision was reversed the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the number of queries resulting in possible identifications from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review discovered the system could generate false positives for Black women almost 100 times more often than for white women at certain settings.

The ministry commented on these findings: “The testing identified that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “The change significantly reduces the effect of bias across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units argued that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

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

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed scant discussion through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of this technology must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A government representative stated: “The Home Office takes the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be pursued without trained officers carefully reviewing the output.”