British Police Forces Campaign to Use Discriminatory Face Scanning Technology

Law enforcement agencies across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version produced fewer investigative leads.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process entails matching a reference photograph of a suspect against a database of more than 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept discrimination in race and gender. Operational ease is a weak argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been known about for over twelve months. Furthermore, police forces argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned laboratory study found the system was more likely to suggest incorrect matches for photos of women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a point where the disparity was significantly reduced.

However, this directive was overturned the following month following complaints from police that the modified technology was generating a lower number of “useful lines of inquiry”. Internal records indicate the higher threshold reduced the proportion of searches that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent NPL study found the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for white women at specific configurations.

The Home Office stated on these findings: “Our evaluation identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic returned results of limited benefit”.

Broader Rollout Plans

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

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed very little consideration in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has undertaken through the equality initiative are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must meet 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 findings of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without specialist personnel carefully reviewing the results.”