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Police forces across the UK successfully lobbied to deploy a facial recognition system acknowledged as discriminatory against women, youths, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

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

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This admission came after a study by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at significantly higher rates than white men. The Home Office said it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

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

Police bosses were notified of the system's bias in late 2024. The government-ordered laboratory study found the system was had a higher probability to produce false positives for photos of women, individuals of Black ethnicity, 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 increased to a level where the bias was greatly diminished.

However, this directive was reversed the next month after forces complained that the modified technology was generating fewer “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries resulting in possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest independent review discovered the system could generate incorrect matches for Black women almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office commented on these findings: “Our evaluation identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's confidence threshold, the police records state: “This adjustment greatly lessens the effect of bias across protected characteristics of ethnicity, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion in race action plan meetings of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination the police has made via the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A government representative said: “We treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will support police to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”