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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as biased against women, youths, and individuals from minority ethnic backgrounds, following complaints that a less biased version generated a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was biased. This admission followed a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept biases in ethnicity and sex. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to address the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce incorrect matches for images depicting females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body ordered that the accuracy setting required for possible hits be raised to a level where the bias was greatly diminished.

However, this decision was reversed the next month after forces complained that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of searches that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review discovered the system could produce false positives for Black women nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office stated on these findings: “The testing found that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents further note that police units complained that “a previously useful tool returned outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, commented: “There was scant consideration in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into wider practice. Our reports have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “We treat the conclusions of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This gamechanging technology will assist police to put criminals and rapists behind bars. There is officer review in every step of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the output.”