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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against females, youths, and members of ethnic minority groups, after complaining that a less biased version generated fewer 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 person of interest against a database of over 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Convenience is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned NPL review concluded the system was more likely to produce false positives for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a level where the bias was significantly reduced.

However, this directive was reversed the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the higher threshold reduced the number of queries that yielded possible identifications from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest independent review found the system could produce false positives for Black women nearly a hundred times more often than for white women at certain settings.

The ministry commented on these results: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on operational effectiveness”. The papers add that forces argued that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “We takes the conclusions of the study seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be taken without specialist personnel meticulously examining the output.”