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Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be discriminatory against females, youths, and members of minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission followed a review by the government's National Physical Laboratory 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”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in race and sex. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

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

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to produce incorrect matches for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for potential matches be raised to a level where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the modified technology was producing a lower number of “investigative leads”. Internal records indicate the stricter setting cut the proportion of queries that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the recent independent review found the system could produce false positives for Black women almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these findings: “Our evaluation found that in a limited set of circumstances the algorithm is more likely to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's accuracy setting, the police records note: “The change significantly reduces the effect of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units complained that “a once effective tactic returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little discussion through equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“Any use of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report seriously and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This gamechanging technology 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.”