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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as discriminatory against females, youths, and members of ethnic minority groups, after complaining that a less biased version generated fewer potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office admitted last week that the system was biased. This admission came after a study by the government's National Physical Laboratory determined it misidentified Black and Asian people and women at significantly higher rates than white men. The ministry said it “had acted on the findings”.

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

Known Issue

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was overturned the next month following complaints from police that the adjusted system was producing fewer “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of searches that yielded potential matches from 56% to a just 14%.

Profound Inequalities

Although the authorities declined to specify what setting is now in operation, the latest independent review discovered the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

The ministry stated on these results: “Our evaluation found 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

Describing the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers further note that police units argued that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week public review on its proposals to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “We observed very little consideration through race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

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

Official Statement

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

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is officer review in every step of the process and no arrest or charge would be pursued without specialist personnel meticulously examining the output.”