British Police Forces Lobbied to Use Biased Facial Recognition Systems

Police forces across the UK successfully lobbied to deploy a facial recognition system known to be biased against females, youths, and individuals from minority ethnic backgrounds, following complaints that a less biased version produced fewer investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This procedure involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This acknowledgment came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept biases in ethnicity and sex. Operational ease is a poor 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 lobbied to reverse an initial decision that was designed to mitigate the problem.

Senior officers were notified of the system's bias in September 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this decision was reversed the next month following complaints from police that the modified technology was producing a lower number of “investigative leads”. Internal records show the higher threshold reduced the proportion of searches resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

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

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents further note that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has described the tool as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

Abimbola Johnson, head 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 facial recognition rollout despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate once again that the anti-racism commitments policing has made via the race action plan are not being translated into wider practice. Independent assessments have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must adhere to strict national standards, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “The Home Office treat the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no further action would be taken without specialist personnel meticulously examining the results.”