🔗 Share this article

Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, youths, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This procedure entails matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This admission followed a study by the government's National Physical Laboratory found it misidentified Black and Asian people and females at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes useful if users tolerate discrimination in race and sex. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned NPL review found the system was more likely to produce false positives for photos of women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be increased to a level where the bias was significantly reduced.

However, this directive was overturned the next month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the number of queries that yielded potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the recent independent review discovered the system could produce incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at specific configurations.

The ministry commented on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents state: “The change significantly reduces the effect of discrimination across protected characteristics of race, generation and sex but had a substantially detrimental effect on police efficiency”. The papers further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “biggest breakthrough since genetic fingerprinting”.

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 in race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination policing has made through the equality initiative are not being translated into broader operations. Independent assessments have warned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and poor data collection already persist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the conclusions of the study with utmost gravity and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”