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Police forces across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The Home Office said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept biases in race and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a point where the bias was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was generating a lower number of “investigative leads”. Internal records show the stricter setting cut the number of queries that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent NPL study found the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The ministry stated on these results: “The testing found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that police units complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched 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”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “We observed very little discussion through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken through the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny 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.”

Home Office Response

A government representative said: “We takes the conclusions of the study with utmost gravity and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”