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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system known to be biased against women, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced fewer investigative leads.

The Technology in Practice

UK forces use the national police database to conduct retrospective facial recognition searches. This process entails matching a “probe image” of a suspect against a repository of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

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

“This raises the question of whether facial recognition only becomes useful if users tolerate biases in race and gender. Convenience is a poor 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 initial decision that was designed to mitigate 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 produce false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be raised to a level where the bias was significantly reduced.

However, this directive was overturned the following month after forces complained that the adjusted system was generating fewer “investigative leads”. NPCC documents indicate the stricter setting reduced the number of queries that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the recent independent review found the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office stated on these results: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “The change significantly reduces the effect of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that forces complained that “a once effective tactic now delivered 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. Policing minister Sarah Jones has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “We observed scant consideration in equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

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

Official Statement

A government representative said: “The Home Office treat the conclusions 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 trialled early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police 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.”