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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against women, youths, and individuals from ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

The Technology in Practice

British police utilize the national police database to carry out searches using historical face recognition. This procedure entails 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 conceded last week that the system was biased. This admission came after a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and females at much greater frequency than white men. The Home Office said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept biases in ethnicity and sex. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest false positives for images depicting women, 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 potential matches be increased to a level where the bias was greatly diminished.

However, this decision was overturned the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. NPCC documents show the stricter setting reduced the number of queries that yielded possible identifications from over half to a just 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the latest independent review found the system could generate false positives for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of race, generation and sex but had a substantially detrimental effect on police efficiency”. The papers add that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week public review on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion through race action plan meetings of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into broader operations. Our reports have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must meet strict national standards, be subject to external review, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

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

“The foremost aim is protecting the public. This revolutionary tool will support police to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without specialist personnel meticulously examining the results.”