🔗 Share this article

Police forces across the United Kingdom effectively campaigned to use a face scanning system known to be biased against women, young people, and individuals from ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This process entails comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This acknowledgment followed a study by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate biases in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been recognized for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a level where the disparity was greatly diminished.

However, this directive was reversed the next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of queries that yielded possible identifications from 56% to a just 14%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the latest independent review discovered the system could produce false positives for Black women nearly a hundred times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The papers add that forces argued that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “biggest breakthrough since DNA matching”.

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 clear relevance with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into broader operations. Our reports have cautioned that innovative tools are being rolled out in a landscape where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“All deployment 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 takes the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support police to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”