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Police forces across the UK effectively campaigned to use a face scanning system known to be discriminatory against women, youths, and individuals from ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

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

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability to produce incorrect matches for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a point where the disparity was greatly diminished.

However, this decision was overturned the next month following complaints from police that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the stricter setting reduced the number of searches that yielded potential matches from over half to a just 14%.

Severe Disparities

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

The Home Office stated on these findings: “The testing found that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The documents add that police units argued that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed very little consideration in equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has made via the race action plan are failing to be integrated 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 meet strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A government representative said: “The Home Office takes the findings of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim 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 procedure and no arrest or charge would be taken without trained officers carefully reviewing the output.”