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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was biased. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry stated it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate discrimination in race and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was reversed the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the proportion of searches resulting in potential matches from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office commented on these findings: “Our evaluation found 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

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age 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 outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration in equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the report seriously and we have already taken action. 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 protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the output.”