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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

British police utilize the national police database to conduct retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a repository of over 19 million mugshots to find potential matches.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission followed a review by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest false positives for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be increased to a point where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records indicate the higher threshold reduced the number of queries that yielded potential matches from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent NPL study found the system could generate incorrect matches for Black women nearly a hundred times more often than for white women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the effect of bias across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed scant discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments policing has made via the equality initiative are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We treat the findings of the report with utmost gravity 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 early next year and will be undergo further assessment.

“Our priority 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 pursued without specialist personnel carefully reviewing the results.”