British Police Forces Lobbied to Employ Biased Face Scanning Technology

Law enforcement agencies across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as biased against females, young people, and members of minority ethnic backgrounds, following complaints that a more accurate version produced fewer potential suspects.

The Technology in Practice

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

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females 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 biases in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The government-ordered laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a level where the bias was greatly diminished.

However, this decision was overturned the next month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records show the higher threshold cut the proportion of searches that yielded possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest NPL study discovered the system could generate false positives for Black women nearly a hundred times more often than for white women at specific configurations.

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

Operational Effectiveness vs. Bias

Outlining 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 protected characteristics of race, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month consultation on its plans to expand 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

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, said: “We observed very little discussion in race action plan meetings of the technology deployment despite clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has undertaken through the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the conclusions of the study seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”