🔗 Share this article

Police forces across the United Kingdom successfully lobbied to use a facial recognition system known to be biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This process involves comparing a reference photograph of a suspect against a database of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission came after a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was had a higher probability 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 ordered that the accuracy setting required for potential matches be raised to a level where the bias 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 “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the number of queries that yielded possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent independent review found the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

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

Balancing Utility and Fairness

Describing the impact of the brief increase to the system's accuracy setting, the police records note: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The papers add that police units argued that “a previously useful tool returned outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed scant discussion in race action plan meetings of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations show yet again that the anti-racism commitments the police has made via the race action plan are not being translated into broader operations. Our reports have cautioned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

A government representative stated: “The Home Office treat the findings of the study with utmost gravity and we have implemented changes. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist officers 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.”