🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to use a facial recognition system acknowledged as biased against females, youths, and individuals from ethnic minority groups, after complaining that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This process entails comparing a reference photograph of a person of interest against a repository of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “had acted on the findings”.

“This raises the question of whether this technology only becomes useful if users accept biases in race and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

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

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of women, Black people, and those under 40 years old.

A Reversed Decision

In response, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was overturned the following month after forces complained that the adjusted system was producing a lower number of “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study discovered the system could generate false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The ministry commented on these results: “The testing found that in a limited set of circumstances the algorithm is more likely to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the impact of discrimination across protected characteristics of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has labeled the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was very little discussion through race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments policing has made via the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, inadequate oversight and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested in the coming months and will be undergo evaluation.

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