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Police forces across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against females, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated fewer potential suspects.

How the System Works

UK forces utilize the national police database to carry out retrospective facial recognition searches. This procedure entails matching a “probe image” of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office conceded last week that the technology was flawed. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The ministry said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users accept discrimination in ethnicity and sex. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce incorrect matches for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body mandated that the accuracy setting required for potential matches be increased to a level where the disparity was greatly diminished.

However, this decision was reversed the following month after forces complained that the adjusted system was producing fewer “investigative leads”. Internal records show the stricter setting reduced the number of queries that yielded possible identifications from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent independent review found the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at specific configurations.

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

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents note: “The change greatly lessens the effect of discrimination across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a previously useful tool returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has described 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, commented: “There was very little consideration in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination policing has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and poor data collection already persist.

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

Official Statement

A Home Office spokesperson said: “We takes the findings of the report with utmost gravity and we have already taken action. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo evaluation.

“Our priority is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be pursued without trained officers meticulously examining the output.”