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Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This admission came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate discrimination in race and gender. Convenience is a weak argument for overriding basic freedoms.”

Known Issue

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

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce false positives for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a point where the disparity was significantly reduced.

However, this directive was overturned 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 reduced the proportion of queries that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent NPL study discovered the system could generate false positives for Black women almost 100 times more often than for Caucasian women at specific configurations.

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

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the police records state: “The change significantly reduces the impact of bias across protected characteristics of ethnicity, age and sex but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a once effective tactic returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

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

“This disclosure show once again that the pledges to combat discrimination the police has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“Our priority 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 procedure and no arrest or charge would be pursued without trained officers carefully reviewing the results.”