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Police forces across the UK effectively campaigned to use a face scanning system known to be biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This procedure entails matching a “probe image” of a suspect against a database of more than 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office conceded last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept biases in race and gender. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce false positives for images depicting 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 possible hits be increased to a level where the bias was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the number of searches resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study found the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the effect of bias across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “There was scant consideration through race action plan meetings of the facial recognition rollout even with clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments policing has undertaken via the race action plan are not being translated into wider practice. Our reports have warned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the report seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the output.”