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Police forces across the UK successfully lobbied to deploy a facial recognition system known to be discriminatory against females, youths, and individuals from ethnic minority groups, after complaining that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This procedure entails matching a “probe image” of a person of interest against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate discrimination in ethnicity and sex. Convenience is a poor argument for disregarding basic freedoms.”

Known Issue

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

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

A Policy U-Turn

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

However, this decision was overturned the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the higher threshold reduced the proportion of queries that yielded potential matches from 56% to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the recent independent review discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The ministry commented on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the effect of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units argued that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the national policing equality strategy, said: “There was very little discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken through the equality initiative are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of facial recognition must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than compounds racial disparity.”

Home Office Response

A government representative stated: “The Home Office treat the findings of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the process and no arrest or charge would be taken without specialist personnel meticulously examining the results.”