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

How the System Works

UK forces use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a “probe image” of a person of interest against a repository of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission came after a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at much greater frequency than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept discrimination in race and gender. Convenience is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for over twelve months. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce incorrect matches for photos of women, Black people, and those aged 40 and under.

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 significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records indicate the higher threshold reduced the number of searches that yielded possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the latest independent review discovered 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: “Our evaluation identified that in a limited set of circumstances the software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a significant negative impact on police efficiency”. The papers add that police units complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the police race action plan, said: “There was very little discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made through the race action plan are not being translated into wider practice. Our reports have cautioned that new technologies are being implemented in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the results.”