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Police forces across the UK successfully lobbied to use a face scanning system acknowledged as biased against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails comparing a “probe image” of a suspect against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users tolerate biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

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 mitigate the problem.

Police bosses were notified of the system's bias in late 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 aged 40 and under.

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 bias was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was producing fewer “investigative leads”. NPCC documents show the stricter setting cut the proportion of queries that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the recent NPL study discovered the system could generate false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the police records note: “The change significantly reduces the impact of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units argued that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant discussion through equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments policing has made through the equality initiative are not being translated into broader operations. Our reports have warned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A government representative said: “We treat the findings of the study seriously and we have implemented changes. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist police 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 specialist personnel carefully reviewing the output.”