🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to deploy a facial recognition system known to be biased against females, youths, and members of ethnic minority groups, following complaints that a less biased version produced a reduced number of potential suspects.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This process entails comparing a “probe image” of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

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

“This raises the question of whether this technology only becomes effective if users accept discrimination in race and sex. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest false positives for images depicting 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 confidence threshold required for potential matches be raised to a point where the bias was significantly reduced.

However, this decision was reversed the next month after forces complained that the modified technology was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of queries resulting in possible identifications from 56% to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study found the system could generate false positives for Black women almost 100 times more frequently than for white women at specific configurations.

The ministry commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the effect of discrimination across protected characteristics of race, generation and sex but had a significant negative impact on police efficiency”. The documents further note that police units complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has made via the equality initiative are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A government representative 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 no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the output.”