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Law enforcement agencies across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against females, youths, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept biases in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce false positives for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for potential matches be increased to a level where the bias was greatly diminished.

However, this directive was reversed the following month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the number of searches resulting in possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the recent NPL study discovered the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the impact of discrimination across protected characteristics of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the police race action plan, said: “There was scant discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has undertaken via the race action plan are not being translated into broader operations. Our reports have warned that innovative tools are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet rigorous official guidelines, be subject to external review, and prove 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 already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be tested early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without trained officers carefully reviewing the results.”