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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system known to be discriminatory against females, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated fewer investigative leads.

How the System Works

UK forces utilize the national police database to conduct searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a database of over 19 million mugshots to find potential matches.

Admitted Bias

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

“It prompts the question of whether facial recognition only becomes effective if users accept biases in ethnicity and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest false positives for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the bias was significantly reduced.

However, this directive was overturned the next month following complaints from police that the adjusted system was generating fewer “investigative leads”. Internal records show the stricter setting reduced the number of searches resulting in potential matches from 56% to a just under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest NPL study 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 Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of race, age and sex but had a significant negative impact on operational effectiveness”. The papers further note that police units complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was very little discussion in race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made through the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must adhere to strict national standards, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the conclusions of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the output.”