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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This process involves matching a “probe image” of a suspect against a repository of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept discrimination in race and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision that was intended to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of queries resulting in possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the latest NPL study found the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that forces complained that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

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

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was very little consideration through race action plan meetings of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has made through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Home Office Response

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 independently tested 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 ensuring public safety. This revolutionary tool will support officers 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 trained officers meticulously examining the results.”