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Police forces across the United Kingdom successfully lobbied to deploy a face scanning system known to be discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out searches using historical face recognition. This procedure involves matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept biases in race and gender. Operational ease is a weak argument for overriding basic freedoms.”

Known Issue

Internal documents show that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the system's bias in late 2024. The Home Office-commissioned NPL review 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 Reversed Decision

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

However, this directive was reversed the next month after forces complained that the modified technology was generating a lower number of “investigative leads”. Internal records indicate the higher threshold reduced the number of searches resulting in possible identifications from over half to a just 14%.

Severe Disparities

Although the authorities refused to say what setting is now in operation, the latest NPL study found the system could generate incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The ministry commented on these findings: “The testing 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 effect of the brief increase to the system's confidence threshold, the police records state: “The change greatly lessens 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 previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police Sarah Jones has described the technology 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 police race action plan, commented: “There was scant consideration through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show once again that the anti-racism commitments the police has made through the race action plan are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “The Home Office takes the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be pursued without trained officers carefully reviewing the output.”