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Police forces across the UK effectively campaigned to deploy a facial recognition system known to be discriminatory against females, youths, and members of ethnic minority groups, after complaining that a more accurate version generated fewer potential suspects.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of over 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was flawed. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered laboratory study found the system was more likely to suggest false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a level where the disparity was greatly diminished.

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

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the impact of bias across legally safeguarded attributes of race, generation and gender but had a significant negative impact on police efficiency”. The documents further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was scant consideration through equality strategy sessions of the technology deployment even with clear relevance with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into broader operations. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the study seriously and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be pursued without trained officers meticulously examining the results.”