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Police forces across the UK effectively campaigned to use a face scanning system known to be biased against females, youths, and individuals from minority ethnic backgrounds, after complaining that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

British police use the police national database (PND) to carry out searches using historical face recognition. This procedure entails comparing a reference photograph of a person of interest against a database of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission came after a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes useful if users accept biases in race and sex. Operational ease is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was designed to mitigate 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 photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a point where the disparity was greatly diminished.

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries that yielded potential matches from over half to a mere under 15%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the latest independent review found the system could generate false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing identified that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the police records note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, age and sex but had a significant negative impact on police efficiency”. The documents add that forces complained that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its plans to widen the use of facial recognition technology. The minister for police Sarah Jones has labeled the technology 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, commented: “There was scant consideration in race action plan meetings of the facial recognition rollout even with clear relevance with the plan’s concerns.

“These revelations show once again that the anti-racism commitments the police has undertaken via the equality initiative are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering already persist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative said: “The Home Office takes the findings of the study seriously and we have implemented changes. A new algorithm has been independently tested 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 ensuring public safety. This gamechanging technology will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without specialist personnel meticulously examining the results.”