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Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system acknowledged as biased against women, youths, and members of ethnic minority groups, after complaining that a less biased version produced fewer investigative leads.

How the System Works

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the technology was flawed. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and women at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users tolerate discrimination in race and sex. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement 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 laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a level where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold reduced the proportion of searches that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the recent NPL study found the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The ministry commented on these results: “Our evaluation identified that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a once effective tactic now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “There was very little discussion in 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 the police has undertaken through the race action plan are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We takes the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be pursued without specialist personnel meticulously examining the results.”