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Law enforcement agencies across the UK successfully lobbied to use a facial recognition system known to be discriminatory against women, young people, and members of 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 carry out searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to find potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate biases in race and sex. Convenience is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered laboratory study found the system was had a higher probability to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, 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 directive was overturned the following month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents show the stricter setting reduced the number of queries resulting in potential matches from 56% to a just under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent independent review discovered the system could produce incorrect matches for women of Black heritage almost 100 times more often than for white women at certain settings.

The ministry commented on these findings: “Our evaluation found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of bias across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “We observed scant consideration in equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments the police has undertaken via the equality initiative are not being translated into broader operations. Our reports have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will support police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be pursued without specialist personnel meticulously examining the results.”