🔗 Share this article

Police forces across the UK successfully lobbied to deploy a face scanning system acknowledged as biased against women, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

The Technology in Practice

UK forces use the national police database to conduct retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of over 19 million mugshots to identify potential matches.

Admitted Bias

The Home Office admitted last week that the technology was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate biases in race and gender. Operational ease is a weak argument for disregarding fundamental rights.”

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 designed to address the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was had a higher probability to suggest false positives for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body mandated that the confidence threshold required for possible hits be increased to a point where the bias was greatly diminished.

However, this directive was overturned the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of searches that yielded potential matches from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent NPL study found the system could produce false positives for women of Black heritage almost 100 times more often than for white women at certain settings.

The Home Office commented on these findings: “The testing identified that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The documents further note that forces complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has labeled the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “We observed very little consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken via the race action plan are not being translated into broader operations. Our reports have cautioned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A government representative 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 demonstrated no measurable discrimination. It will be trialled early next year and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be pursued without trained officers meticulously examining the results.”