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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, youths, and individuals from ethnic minority groups, after complaining that a more accurate version produced a reduced number of potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This process involves matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at much greater frequency than white men. The ministry stated it “had acted on the findings”.

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

Known Issue

Internal documents show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was more likely to produce false positives for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a point where the bias was significantly reduced.

However, this directive was reversed the following month following complaints from police that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting reduced the proportion of searches resulting in potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The Home Office commented on these results: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents further note that forces complained that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “We observed very little discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken through the race action plan are not being translated into broader operations. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

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

Home Office Response

A Home Office spokesperson said: “The Home Office treat the conclusions of the study seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“Our priority is protecting the public. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be taken without trained officers meticulously examining the results.”