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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against women, young people, and individuals from minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct searches using historical face recognition. This process involves matching a “probe image” of a suspect against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This acknowledgment followed a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users accept discrimination in race and gender. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the stricter setting reduced the number of queries resulting in potential matches from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent NPL study discovered the system could generate false positives for Black women almost 100 times more frequently than for white women at specific configurations.

The Home Office stated on these results: “The testing identified that in a limited set of circumstances the software is more likely to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records state: “The change greatly lessens the impact of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The papers add that forces complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, commented: “There was scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination the police has undertaken via the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the study with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be taken without trained officers meticulously examining the output.”