UK Police Forces Campaign to Employ Discriminatory Face Scanning Technology

Police forces across the UK successfully lobbied to use a face scanning system known to be biased against females, young people, and members of ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to conduct searches using historical face recognition. This process involves matching a “probe image” of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept discrimination in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to address the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered laboratory study found the system was had a higher probability to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, 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 generating fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the number of queries that yielded 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 NPL study discovered the system could generate incorrect matches for Black women nearly a hundred times more frequently than for white women at specific configurations.

The ministry stated on these results: “Our evaluation identified that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The papers add that forces complained that “a once effective tactic returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, said: “We observed scant consideration through race action plan meetings of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We treat the findings of the study with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”