British Law Enforcement Agencies Campaign to Employ Biased Face Scanning Systems

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

How the System Works

UK forces utilize 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 database of more than 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at significantly higher rates than white men. The ministry said it “took steps on the findings”.

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

Long-Standing Problem

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be increased to a point where the disparity was greatly diminished.

However, this decision was reversed the next month after forces complained that the modified technology was producing a lower number of “investigative leads”. NPCC documents show the stricter setting cut the proportion of queries resulting in potential matches from 56% to a just 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent NPL study found the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office commented on these results: “Our evaluation found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and sex but had a substantially detrimental effect 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 plans to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “biggest breakthrough 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 discussion through race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has made through the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

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

Official Statement

A Home Office spokesperson said: “We takes the conclusions of the report with utmost gravity 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 in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without specialist personnel carefully reviewing the results.”