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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as biased against women, youths, and individuals from ethnic minority groups, following complaints that a more accurate version generated fewer potential suspects.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

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

Known Issue

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was overturned the following month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the number of queries that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what setting is now in operation, the recent independent review discovered the system could produce false positives for women of Black heritage almost 100 times more frequently than for Caucasian 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 wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces 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 the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration in equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be pursued without trained officers carefully reviewing the output.”