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Police forces across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves matching a reference photograph of a person of interest against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the technology was flawed. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The Home Office said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes effective if users tolerate discrimination in ethnicity and sex. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

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

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest false positives for photos of females, 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 disparity was greatly diminished.

However, this decision was overturned the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of searches resulting in possible identifications from 56% to a just under 15%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent NPL study found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's accuracy setting, the police records note: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on operational effectiveness”. The documents add that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “There was very little discussion through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations show yet again that the pledges to combat discrimination the police has undertaken through the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”