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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against females, young people, and members of ethnic minority groups, after complaining that a more accurate version generated a reduced number of potential suspects.

How the System Works

British police utilize the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry said it “took steps on the findings”.

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

Known Issue

Internal documents show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was had a higher probability to produce incorrect matches for images depicting women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body mandated that the confidence threshold required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the adjusted system was producing fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries that yielded possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what threshold is now in operation, the recent independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for white women at specific configurations.

The ministry commented on these findings: “Our evaluation found that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents add that police units argued that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration through equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the anti-racism commitments policing has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A government representative stated: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”