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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of potential suspects.

How the System Works

British police utilize the national police database to carry out searches using historical face recognition. This procedure involves comparing a “probe image” of a person of interest against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at significantly higher rates than white men. The Home Office stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate biases in race and sex. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

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

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents show the higher threshold cut the number of queries that yielded possible identifications from 56% to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest NPL study found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The ministry commented on these findings: “The testing identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on police efficiency”. The papers add that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “We observed scant discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet 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 warned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson said: “The Home Office takes the conclusions of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support 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 specialist personnel carefully reviewing the results.”