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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against females, youths, and members of minority ethnic backgrounds, after complaining that a less biased version produced fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a “probe image” of a person of interest against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office conceded last week that the technology was flawed. This acknowledgment came after a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office stated it “took steps on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate discrimination in race and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a level where the bias was significantly reduced.

However, this decision was reversed the following month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. NPCC documents show the higher threshold cut the number of searches resulting in possible identifications from over half to a mere 14%.

Profound Inequalities

Although the authorities refused to say what setting is currently used, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The Home Office commented on these results: “The testing identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “This adjustment greatly lessens the impact of bias across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “We observed very little discussion through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations show once again that the anti-racism commitments policing has made via the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative stated: “The Home Office treat the findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim 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 pursued without specialist personnel meticulously examining the output.”