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Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process entails comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office conceded last week that the technology was flawed. This acknowledgment followed a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users accept discrimination in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the disparity was greatly diminished.

However, this directive was reversed the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents indicate the stricter setting reduced the number of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the latest NPL study discovered the system could generate incorrect matches for Black women almost 100 times more frequently than for white women at specific configurations.

The ministry stated on these findings: “Our evaluation found that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the impact of bias across protected characteristics of race, generation and gender but had a significant negative impact on police efficiency”. The papers add that forces complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “We observed scant discussion in equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken through the equality initiative are failing to be integrated into broader operations. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office treat the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“Our priority 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 further action would be taken without specialist personnel meticulously examining the results.”