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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against women, young people, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This process involves matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify potential matches.

Admitted Bias

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

“This raises the question of whether this technology only becomes useful if users accept biases in race and gender. Convenience is a weak argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces 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 NPL review found the system was more likely to produce false positives for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was overturned the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. Internal records indicate the higher threshold cut the number of queries resulting in possible identifications from 56% to a just 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the recent independent review discovered the system could generate incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing identified that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of bias across protected characteristics of race, generation and sex but had a significant negative impact on police efficiency”. The papers further note that forces argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “There was scant consideration in race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has undertaken via the equality initiative are not being translated into wider practice. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the study seriously and we have already taken action. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without trained officers meticulously examining the results.”