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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system known to be biased against females, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated fewer potential suspects.

The Technology in Practice

British police use the police national database (PND) to carry out searches using historical face recognition. This procedure entails matching a reference photograph of a person of interest against a repository of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and females at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept biases in race and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal 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.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the proportion of searches resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what threshold is now in operation, the latest NPL study discovered the system could produce false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on police efficiency”. The documents further note that police units complained that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, said: “There was very little discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“These revelations show 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 warned that innovative tools are being rolled out in a context 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 reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the report 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 evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”