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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system acknowledged as biased against females, youths, and individuals from ethnic minority groups, following complaints that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a suspect against a database of over 19 million mugshots to find possible hits.

Admitted Bias

The Home Office admitted last week that the system was biased. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and females at significantly higher rates than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate biases in race and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a level where the disparity was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. Internal records show the stricter setting reduced the number of queries that yielded potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the latest NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “The testing identified that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the impact of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces complained that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion through equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken through the race action plan are not being translated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape 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 ethnic bias.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes the findings of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. 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 apprehend and prosecute offenders. There is human involvement in each stage of the process and no arrest or charge would be taken without trained officers carefully reviewing the output.”