🔗 Share this article

Police forces across the UK successfully lobbied to deploy a facial recognition system known to be discriminatory against females, young people, and individuals from ethnic minority groups, following complaints that a more accurate version generated fewer investigative leads.

How the System Works

UK forces utilize the national police database to carry out retrospective facial recognition searches. This process involves matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and women at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

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

Known Issue

Internal documents show that this bias has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest false positives for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be increased to a point where the bias was significantly reduced.

However, this decision was reversed the following month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the proportion of queries resulting in potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent independent review found the system could generate incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The Home Office stated on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “The change significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month public review on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has described the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was scant consideration through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination the police has made through the race action plan are not being translated into wider practice. Our reports have warned that new technologies are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the output.”