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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This procedure involves matching a “probe image” of a person of interest against a repository of more than 19 million mugshots to find possible hits.

Admitted Bias

The Home Office conceded last week that the technology was biased. This acknowledgment followed a review by the government's National Physical Laboratory found it misidentified Black and Asian people and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents show that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the next month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the number of queries resulting in potential matches from over half to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the recent independent review found the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office commented on these findings: “Our evaluation 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

Outlining the impact of the temporary raise to the system's accuracy setting, the police records note: “This adjustment greatly lessens the effect of discrimination across protected characteristics of race, age and gender but had a significant negative impact on police efficiency”. The documents further note that police units complained that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones 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, said: “We observed scant discussion through race action plan meetings of the technology deployment despite clear relevance with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination the police has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

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

Home Office Response

A government representative stated: “The Home Office treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. 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 pursued without specialist personnel carefully reviewing the output.”