🔗 Share this article

Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a database of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and women at significantly higher rates than white men. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to mitigate the problem.

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

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a level 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”. Internal records show the higher threshold reduced the proportion of searches that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest independent review found the system could generate 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: “The testing found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a once effective tactic returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its plans to widen the use of facial recognition technology. 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 advisory panel for the national policing equality strategy, commented: “There was very little consideration through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has made via the race action plan are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be pursued without trained officers meticulously examining the results.”