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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police use the police national database (PND) to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a suspect against a repository of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept biases in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce incorrect matches for photos of females, Black people, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be increased to a point where the bias was significantly reduced.

However, this directive was overturned the next month following complaints from police that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting cut the number of queries resulting in possible identifications from 56% to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the latest NPL study discovered the system could generate false positives for women of Black heritage almost 100 times more often than for white women at specific configurations.

The ministry commented on these results: “The testing identified that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “The change greatly lessens the effect of discrimination across protected characteristics of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The documents further note that forces complained that “a once effective tactic returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration through race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“These revelations demonstrate once again that the anti-racism commitments the police has made via the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat the findings of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will support police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the results.”