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Police forces across the UK effectively campaigned to deploy a face scanning system acknowledged as biased against women, youths, and individuals from ethnic minority groups, after complaining that a more accurate version generated fewer investigative leads.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This process involves matching a reference photograph of a suspect against a repository of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the technology was flawed. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

“It prompts the issue of whether facial recognition only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Official papers show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces argued to overturn an initial decision that was intended to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The government-ordered laboratory study found the system was more likely to suggest incorrect matches for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a point where the disparity was significantly reduced.

However, this decision was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents show the higher threshold reduced the number of queries resulting in possible identifications from over half to a mere 14%.

Profound Inequalities

Although the authorities refused to say what threshold is currently used, the latest independent review discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these results: “Our evaluation identified that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of discrimination across legally safeguarded attributes of ethnicity, age and sex but had a substantially detrimental effect on police efficiency”. The documents further note that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, commented: “There was very little discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken through the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Home Office Response

A government representative stated: “We takes the conclusions of the report seriously and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be subject to further assessment.

“The foremost aim is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be taken without specialist personnel meticulously examining the output.”