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Police forces across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against women, young people, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to conduct searches using historical face recognition. This procedure involves comparing a “probe image” of a person of interest against a repository of over 19 million custody photos to identify possible hits.

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 determined it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a level where the disparity was greatly diminished.

However, this directive was reversed the following month after forces complained that the modified technology was generating a lower number of “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the number of searches that yielded potential matches from 56% to a just 14%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the latest independent review found the system could produce incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The ministry stated on these findings: “The testing found that in a specific scenarios the algorithm is more likely to incorrectly include 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 police records state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week public review on its proposals to expand the use of biometric scanning systems. 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, head of the advisory panel for the national policing equality strategy, commented: “There was scant consideration through race action plan meetings of the technology deployment even with clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments the police has undertaken via the race action plan are not being translated into broader operations. Independent assessments have warned that innovative tools are being implemented in a context where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office takes the conclusions of the study seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

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