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Police forces across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, youths, and individuals from ethnic minority groups, after complaining that a less biased version produced a reduced number of investigative leads.

How the System Works

British police use the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a suspect against a repository of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This acknowledgment followed a study by the government's National Physical Laboratory found it misidentified Black and Asian people and women at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users tolerate discrimination in race and gender. Convenience is a weak argument for overriding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw 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 informed of the system's bias in late 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this directive was reversed the next month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of queries that yielded potential matches from 56% to a just 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred 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 software is more likely to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the effect of bias across protected characteristics of race, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that police units argued that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, said: “We observed very little discussion through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into broader operations. Our reports have warned that innovative tools are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering already persist.

“All deployment of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Official Statement

A government representative said: “We treat the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be pursued without trained officers carefully reviewing the results.”