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Police forces across the UK effectively campaigned to deploy a facial recognition system known to be biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct searches using historical face recognition. This procedure involves matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in ethnicity and gender. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show 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.

Senior officers were notified of the system's bias in September 2024. The government-ordered NPL review found the system was more likely to suggest incorrect matches for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be raised to a point where the bias was greatly diminished.

However, this directive was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents indicate the stricter setting reduced the proportion of queries resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent NPL study found the system could produce false positives for Black women nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The papers further note that forces argued that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little discussion through equality strategy sessions 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 undertaken through the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We takes the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the results.”