🔗 Share this article

Police forces across the UK effectively campaigned to deploy a face scanning system known to be discriminatory against females, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces utilize the national police database to carry out searches using historical face recognition. This procedure involves comparing a “probe image” of a suspect against a repository of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it misidentified Black and Asian people and women at significantly higher rates than Caucasian males. The ministry said it “took steps on the findings”.

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

Known Issue

Internal documents reveal that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was more likely to produce false positives for images depicting females, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a point where the bias was significantly reduced.

However, this directive was reversed the following month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting reduced the number of queries resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the recent NPL study found the system could generate incorrect matches for Black women nearly a hundred times more frequently than for white women at specific configurations.

The Home Office commented on these results: “The testing identified that in a specific scenarios the algorithm 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 accuracy setting, the NPCC documents state: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The papers further note that police units complained that “a previously useful tool returned outcomes of questionable value”.

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. The minister for police Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion through race action plan meetings of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into wider practice. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and prove it reduces rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. 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 apprehend and prosecute offenders. There is human involvement in every step of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”