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Law enforcement agencies across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated fewer potential suspects.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a repository of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This admission came after a review by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at much greater frequency than white men. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate discrimination in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this directive was overturned the following month following complaints from police that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the stricter setting cut the proportion of searches resulting in potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review found the system could produce false positives for Black women nearly a hundred times more often than for white women at specific configurations.

The Home Office stated on these findings: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise 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 gender but had a significant negative impact on operational effectiveness”. The papers further note that forces complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments policing has undertaken through the equality initiative are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“Our priority is protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”