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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system known to be biased against women, youths, and individuals from minority ethnic backgrounds, following complaints that a less biased version generated fewer investigative leads.

The Technology in Practice

British police use the national police database to carry out searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in race and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this discriminatory flaw has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. NPCC documents show the stricter setting reduced the number of searches that yielded potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest NPL study found the system could produce incorrect matches for Black women nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these findings: “The testing identified that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment greatly lessens the effect of bias across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The papers further note that police units complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

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 consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken via the race action plan are not being translated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Official Statement

A government representative stated: “We treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

“Our priority is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the results.”