🔗 Share this article

Law enforcement agencies across the UK effectively campaigned to use a facial recognition system acknowledged as biased against women, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office stated it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes useful if users tolerate discrimination in race and sex. Operational ease is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be increased to a point where the bias was significantly reduced.

However, this decision was overturned the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the proportion of queries resulting in possible identifications from 56% to a just under 15%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the recent NPL study discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

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

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little discussion through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny 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 exacerbates racial disparity.”

Home Office Response

A government representative stated: “The Home Office takes the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“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 each stage of the procedure and no further action would be taken without trained officers meticulously examining the results.”