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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against females, young people, and individuals from minority ethnic backgrounds, following complaints that a less biased version produced fewer investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was biased. This admission followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Internal documents show that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study 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 Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of queries that yielded potential matches from over half to a mere 14%.

Profound Inequalities

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

The ministry stated on these results: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's accuracy setting, the NPCC documents state: “The change significantly reduces the effect of discrimination 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 argued that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, commented: “We observed scant consideration in race action plan meetings of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination policing 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, weak scrutiny and poor data collection already persist.

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

Official Statement

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“Our priority is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be pursued without specialist personnel meticulously examining the output.”