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Law enforcement agencies across the UK successfully lobbied to deploy a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves matching a reference photograph of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The Home Office said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in race and gender. Convenience is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be increased to a level where the bias was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting reduced the proportion of searches that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study discovered the system could generate false positives for Black women almost 100 times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on police efficiency”. The papers add that forces complained that “a previously useful tool returned results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to expand the use of facial recognition technology. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations show yet 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 context where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “We takes the findings of the report seriously and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no arrest or charge would be taken without trained officers meticulously examining the output.”