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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as discriminatory against females, youths, and members of ethnic minority groups, after complaining that a more accurate version produced fewer potential suspects.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This procedure involves matching a reference photograph of a suspect against a repository of over 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the system was flawed. This acknowledgment followed a study by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers show that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold 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 fewer “useful lines of inquiry”. NPCC documents show the higher threshold cut the proportion of searches resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent independent review found the system could generate false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found 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

Describing the effect of the temporary raise to the system's confidence threshold, the police records note: “The change significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant discussion through equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken via the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds 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 new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the output.”