Police forces across the UK successfully lobbied to use a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.
British police use the national police database to carry out retrospective facial recognition searches. This procedure involves matching a “probe image” of a suspect against a database of over 19 million custody photos to find potential matches.
The Home Office conceded last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.
“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Convenience is a weak argument for disregarding basic freedoms.”
Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.
Senior officers were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce incorrect matches for photos of women, individuals of Black ethnicity, and those under 40 years old.
In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be increased to a point where the disparity was significantly reduced.
However, this decision was reversed the following 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 number of searches resulting in potential matches from 56% to a just under 15%.
Although the authorities declined to specify what threshold is now in operation, the latest independent review found the system could generate false positives for Black women almost 100 times more frequently than for Caucasian women at specific configurations.
The ministry commented on these results: “The testing found that in a specific scenarios the software is more likely to incorrectly include some population segments in its search results.”
Outlining the effect of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the effect of discrimination across protected characteristics of race, generation and gender but had a significant negative impact on operational effectiveness”. The papers add that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.
Meanwhile, the UK administration has launched a ten-week consultation 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”.
The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, said: “There was scant consideration through equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.
“This disclosure show yet again that the pledges to combat discrimination the police has made via the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being implemented 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 independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”
A Home Office spokesperson said: “We takes the findings of the study seriously and we have already taken action. 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 subject to further assessment.
“Our priority is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be taken without trained officers meticulously examining the results.”
A passionate textile artist and community organizer who loves inspiring others through creative sewing projects.
