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Law enforcement agencies across the United Kingdom successfully lobbied to use a face scanning system known to be biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to conduct retrospective facial recognition searches. This process involves matching a “probe image” of a person of interest against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission followed a study by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in race and gender. Convenience is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the higher threshold reduced the number of searches that yielded potential matches from 56% to a just 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The Home Office commented on these findings: “The testing found that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The documents add that police units 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 consultation on its plans to expand the use of facial recognition technology. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was very little discussion through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination the police has made through the race action plan are failing to be integrated into broader operations. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

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

Official Statement

A Home Office spokesperson said: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, 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 police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be pursued without specialist personnel meticulously examining the results.”