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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version generated fewer potential suspects.

The Technology in Practice

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

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents show that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered 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 reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a point where the disparity was greatly diminished.

However, this directive was overturned the following month following complaints from police that the adjusted system was producing fewer “investigative leads”. NPCC documents indicate the higher threshold reduced the number of searches resulting in possible identifications from over half to a just under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the recent independent review found the system could produce incorrect matches for Black women almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office stated on these results: “The testing identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's accuracy setting, the police records note: “The change significantly reduces the effect of bias across protected characteristics of race, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little discussion through race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations demonstrate once again that the anti-racism commitments policing has undertaken through the race action plan are not being translated into broader operations. Independent assessments have warned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight 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 Home Office spokesperson said: “The Home Office takes the findings of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the output.”