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Law enforcement agencies across the UK effectively campaigned to use a facial recognition system known to be discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process entails matching a “probe image” of a person of interest against a database of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses 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 aged 40 and under.

A Reversed Decision

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

However, this directive was overturned the following month after forces complained that the modified technology was generating a lower number of “investigative leads”. Internal records indicate the stricter setting reduced the number of searches resulting in potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest NPL study found the system could generate false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The papers add that police units complained that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “We observed very little consideration through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination the police has undertaken via the equality initiative are not being translated 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 continue to exist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “The Home Office treat the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”