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Police forces across the United Kingdom successfully lobbied to use a facial recognition system acknowledged as discriminatory against women, youths, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of potential suspects.

How the System Works

British police use the national police database to carry out searches using historical face recognition. This procedure involves matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This admission came after a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes useful if users tolerate discrimination in ethnicity and gender. Convenience is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for more than a year. Furthermore, police forces argued to overturn an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to suggest false positives for images depicting women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the bias was significantly reduced.

However, this directive was reversed the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the number of queries resulting in potential matches from 56% to a just 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is now in operation, the latest NPL study discovered the system could generate incorrect matches for Black women almost 100 times more often than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing identified that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the impact of discrimination across protected characteristics of race, age and sex but had a significant negative impact on operational effectiveness”. The documents further note that police units complained that “a previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion in race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments policing has made via the equality initiative are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be pursued without specialist personnel carefully reviewing the results.”