British Police Forces Campaign to Use Biased Facial Recognition Systems

Police forces across the United Kingdom effectively campaigned to deploy a facial recognition system known to be discriminatory against females, youths, and individuals from ethnic minority groups, after complaining that a more accurate version produced a reduced number of investigative leads.

How the System Works

UK forces use the police national database (PND) to conduct searches using historical face recognition. This process involves comparing a “probe image” of a person of interest against a repository of more than 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This acknowledgment followed a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females 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 effective if users tolerate discrimination in race and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to suggest false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be raised to a point where the bias was greatly diminished.

However, this decision was overturned the next month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents show the stricter setting reduced the number of queries resulting in possible identifications from 56% to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the latest NPL study discovered the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The Home Office stated on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, generation and sex but had a significant negative impact on operational effectiveness”. The papers add that forces complained that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed very little discussion through equality strategy sessions of the technology deployment despite clear relevance with the plan’s concerns.

“This disclosure show once again that the pledges to combat discrimination policing has made through the race action plan are failing to be integrated into broader operations. Our reports have warned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the findings of the study seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

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