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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, youths, and individuals from ethnic minority groups, following complaints that a less biased version generated fewer potential suspects.

How the System Works

British police utilize the national police database to carry out retrospective facial recognition searches. This process entails matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and females at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate biases in race and sex. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned NPL review 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 response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be increased to a point where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the adjusted system was generating fewer “investigative leads”. NPCC documents show the higher threshold cut the number of searches that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the latest independent review found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these findings: “The testing identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the impact of bias across protected characteristics of race, age and gender but had a significant negative impact on police efficiency”. The papers further note that police units complained 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 consultation on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was very little discussion through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A government representative said: “We treat 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 trialled early next year and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be pursued without trained officers carefully reviewing the results.”