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Police forces across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against women, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to carry out retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified Black and Asian people and women at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate biases in ethnicity and sex. Convenience is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for photos of females, Black people, and those aged 40 and under.

A Reversed Decision

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

However, this decision was overturned the next month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records indicate the stricter setting cut the proportion of queries that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

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

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 bias across protected characteristics of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The papers further note that police units complained that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the police race action plan, commented: “There was scant discussion through equality strategy sessions of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“These revelations show once again that the anti-racism commitments policing has made through the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We takes the conclusions of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”