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Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be discriminatory against females, young people, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

British police use the national police database to carry out retrospective facial recognition searches. This procedure involves comparing a reference photograph of a suspect against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

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

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for possible hits be increased to a point where the disparity was significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. Internal records show the stricter setting cut the number of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review discovered the system could produce false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the effect of bias across protected characteristics of ethnicity, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces argued that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “We observed scant discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has made via the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

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

Official Statement

A Home Office spokesperson stated: “We takes the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be pursued without trained officers meticulously examining the output.”