🔗 Share this article

Police forces across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as discriminatory against females, youths, and members of minority ethnic backgrounds, after complaining that a more accurate version produced fewer investigative leads.

How the System Works

British police utilize the national police database to carry out retrospective facial recognition searches. This procedure entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in ethnicity and gender. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was intended to address the problem.

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

A Policy U-Turn

In response, the national police leadership body ordered that the accuracy setting required for potential matches be increased to a level where the bias was greatly diminished.

However, this decision was overturned the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of searches that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office stated on these findings: “Our evaluation found that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's confidence threshold, the police records state: “The change greatly lessens the impact of discrimination across protected characteristics of race, generation and sex but had a substantially detrimental effect on police efficiency”. The documents further note that police units complained that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, commented: “There was scant consideration in equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where ethnic inequalities, inadequate oversight and poor data collection already persist.

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

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the report seriously and we have already taken action. 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 further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”