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Law enforcement agencies across the United Kingdom effectively campaigned to use a facial recognition system known to be biased against females, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced fewer potential suspects.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office conceded last week that the system was biased. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and females at much greater frequency than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the question of whether this technology only becomes effective if users accept discrimination in ethnicity and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to produce incorrect matches for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be raised to a level where the bias was significantly reduced.

However, this directive was overturned the next month after forces complained that the adjusted system was producing fewer “investigative leads”. NPCC documents show the stricter setting reduced the number of searches resulting in possible identifications from 56% to a just 14%.

Profound Inequalities

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

The ministry stated on these findings: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

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

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was very little consideration in race action plan meetings of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has made via the equality initiative are not being translated into wider practice. Our reports have warned that new technologies are being rolled out in a context where racial disparities, 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.”

Official Statement

A Home Office spokesperson stated: “We treat the findings of the study with utmost gravity 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 in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the process and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”