🔗 Share this article

Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against females, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This admission followed a study by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and women at much greater frequency than white men. The ministry stated it “took steps on the findings”.

“This raises the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Convenience is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The Home Office-commissioned NPL review found the system was more likely to produce false positives for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a level where the disparity was significantly reduced.

However, this directive was overturned the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records indicate the higher threshold reduced the proportion of searches that yielded potential matches from 56% to a just 14%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing found that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a once effective tactic now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was scant consideration in race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We takes the conclusions of the report seriously and we have implemented changes. A updated software 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 further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers meticulously examining the output.”