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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, after complaining that a less biased version produced fewer potential suspects.

The Technology in Practice

UK forces use the national police database to carry out searches using historical face recognition. This procedure involves comparing a “probe image” of a suspect against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

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

“It prompts the question of whether this technology only becomes useful if users tolerate biases in race and gender. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review concluded the system was more likely to suggest incorrect matches for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) 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 next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. Internal records indicate the higher threshold reduced the number of searches resulting in potential matches from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest independent review found the system could produce false positives for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The ministry stated on these results: “The testing identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the effect of bias across protected characteristics of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “There was scant discussion through race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be taken without specialist personnel meticulously examining the output.”