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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, young people, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

The Technology in Practice

British police utilize the national police database to conduct retrospective facial recognition searches. This process entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women 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 accept biases in race and sex. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest incorrect matches for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a point where the bias was significantly reduced.

However, this directive was reversed the next month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting reduced the proportion of queries resulting in potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the latest independent review discovered the system could generate incorrect matches for Black women nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing found that in a specific scenarios the algorithm is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed scant consideration through race action plan meetings of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments policing has made through the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the study seriously and we have implemented changes. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”