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Police forces across the UK successfully lobbied to deploy a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, following complaints that a less biased version generated fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves matching a reference photograph of a suspect against a database of more than 19 million custody photos to find potential matches.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes useful if users accept biases in race and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was reversed the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries that yielded possible identifications from 56% to a mere under 15%.

Severe Disparities

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

The ministry stated on these findings: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on police efficiency”. The papers add that forces complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “We observed very little discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must meet strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the study seriously and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be taken without trained officers carefully reviewing the output.”