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

How the System Works

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a suspect against a database of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

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

“It prompts the issue of whether facial recognition only becomes useful if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Police bosses were notified of the system's bias in late 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body ordered that the accuracy setting required for potential matches be increased to a point where the disparity was greatly diminished.

However, this decision was overturned the next month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold reduced the proportion of searches resulting in possible identifications from over half to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry stated on these findings: “The testing found that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the police records state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “most significant advance 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, said: “We observed scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has undertaken via the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and prove it reduces rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”