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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system known to be biased against females, youths, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of potential suspects.

How the System Works

British police utilize the police national database (PND) to carry out searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was flawed. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The ministry stated it “had acted on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate biases in race and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this decision was overturned the next month after forces complained that the modified technology was producing fewer “investigative leads”. NPCC documents show the higher threshold cut the number of searches that yielded possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study discovered the system could generate false positives for Black women nearly a hundred times more often than for white women at certain settings.

The Home Office stated on these results: “The testing identified that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “We observed scant discussion in equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments the police has made via the race action plan are not being translated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

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

Official Statement

A government representative said: “We treat the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be taken without specialist personnel meticulously examining the results.”