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Law enforcement agencies across the UK successfully lobbied to deploy a face scanning system known to be discriminatory against females, young people, and members of ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out searches using historical face recognition. This procedure involves comparing a reference photograph 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 technology was flawed. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the question of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

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 intended to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body 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 next month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records show the higher threshold cut the proportion of queries 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 now in operation, the recent NPL study discovered the system could produce false positives for Black women nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing identified 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 impact of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The papers 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 proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “There was scant discussion through race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“These revelations show once again that the pledges to combat discrimination the police has made via the equality initiative are not being translated into broader operations. Independent assessments have warned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Official Statement

A government representative stated: “The Home Office treat the conclusions of the report with utmost gravity and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no further action would be taken without specialist personnel meticulously examining the results.”