British Police Forces Campaign to Use Discriminatory Face Scanning Systems

Police forces across the UK successfully lobbied to deploy a facial recognition system known to be discriminatory against women, youths, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of potential suspects.

How the System Works

UK forces utilize the police national database (PND) to carry out 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 identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

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

Known Issue

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

Senior officers were notified of the system's bias in late 2024. The government-ordered laboratory study found the system was had a higher probability to suggest false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was overturned the next 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 cut the number of searches that yielded potential matches from 56% to a just 14%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the latest independent review found the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for white women at specific configurations.

The Home Office commented on these findings: “Our evaluation identified that in a limited set of circumstances the software is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's confidence threshold, the police records note: “The change greatly lessens the effect of bias across legally safeguarded attributes of race, age and sex but had a significant negative impact on police efficiency”. The documents add that forces complained that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to widen the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little consideration through equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has made via the race action plan are not being translated into wider practice. Our reports have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson stated: “We treat the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to further assessment.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the process and no arrest or charge would be pursued without trained officers carefully reviewing the results.”