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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against women, youths, and members of ethnic minority groups, after complaining that a less biased version produced fewer potential suspects.

How the System Works

UK forces utilize the national police database to carry out searches using historical face recognition. This procedure entails comparing a “probe image” of a person of interest against a repository of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment followed 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 ministry stated it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest incorrect matches for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a level where the bias was greatly diminished.

However, this decision was reversed the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the stricter setting reduced the proportion of searches resulting in possible identifications from 56% to a just under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent independent review discovered the system could produce incorrect matches for Black women nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its plans to widen the use of facial recognition technology. 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, head of the advisory panel for the national policing equality strategy, said: “There was very little discussion through race action plan meetings of the technology deployment despite clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has undertaken via the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the findings of the study seriously and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”