British Police Forces Lobbied to Employ Discriminatory Face Scanning Technology

Police forces across the UK successfully lobbied to use a face scanning system known to be biased against females, young people, and members of ethnic minority groups, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the national police database to conduct searches using historical face recognition. This process involves comparing a “probe image” of a suspect against a database of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

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

“It prompts the issue of whether this technology only becomes effective if users accept biases in race and sex. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

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

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a point where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of searches that yielded possible identifications from over half to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what threshold is currently used, the recent NPL study found the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a limited set of circumstances the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the police records state: “This adjustment greatly lessens the effect of bias across protected characteristics of race, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that forces complained that “a once effective tactic returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “We observed very little discussion in equality strategy sessions of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments policing has undertaken via the race action plan are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, 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 reduces rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “We treat the conclusions of the study 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 tested early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be pursued without specialist personnel meticulously examining the results.”