🔗 Share this article

Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced fewer potential suspects.

The Technology in Practice

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

Acknowledged Discrimination

The UK interior ministry admitted last week that the technology was biased. This acknowledgment followed a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The ministry said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate biases in race and sex. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses 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 incorrect matches for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body mandated that the accuracy setting required for potential matches be increased to a level where the disparity was significantly reduced.

However, this directive was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the stricter setting reduced the proportion of searches that yielded potential matches from over half to a just under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest NPL study discovered the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office stated on these results: “The testing found that in a limited set of circumstances the algorithm is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool 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, said: “We observed very little discussion through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments policing has undertaken via the equality initiative are not being translated into broader operations. Our reports have warned that new technologies are being rolled out in a context where ethnic inequalities, 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 compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “We treat the findings of the report seriously and we have already taken action. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be undergo further assessment.

“The foremost aim is protecting the public. This revolutionary tool 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 trained officers meticulously examining the results.”