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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as discriminatory against women, youths, and members of ethnic minority groups, following complaints that a less biased version produced a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the national police database to conduct searches using historical face recognition. This procedure entails matching a “probe image” of a suspect against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body mandated that the confidence threshold required for potential matches be raised to a level where the bias was significantly reduced.

However, this directive was overturned the following month after forces complained that the adjusted system was generating a lower number of “investigative leads”. 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 Home Office and NPCC declined to specify what threshold is currently used, the recent NPL study found the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

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

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units argued that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, commented: “We observed very little discussion in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”