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Police forces across the UK effectively campaigned to deploy a facial recognition system acknowledged as biased against females, young people, and individuals from ethnic minority groups, following complaints that a less biased version produced a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office conceded last week that the system was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate biases in ethnicity and sex. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce false positives for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

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

However, this decision was reversed the following month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of queries resulting in possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what setting is now in operation, the latest independent review discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing found 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 temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little consideration in race action plan meetings of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments policing has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office 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 in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”