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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as discriminatory against women, young people, and individuals from minority ethnic backgrounds, after complaining 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 person of interest against a repository of more than 19 million custody photos to find possible hits.

Admitted Bias

The Home Office admitted last week that the system was flawed. This acknowledgment came after a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in race and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review concluded the system was had a higher probability to produce incorrect matches for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the next month following complaints from police that the modified technology was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the proportion of queries that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the latest independent review found the system could generate incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents state: “The change significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week public review on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “There was very little discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the study with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”