UK Police Forces Campaign to Employ Biased Face Scanning Systems

Law enforcement agencies across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as biased against females, young people, and members of ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

How the System Works

British police use the national police database to conduct retrospective facial recognition searches. This procedure involves comparing a “probe image” of a suspect against a database of over 19 million custody photos to find potential matches.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This acknowledgment came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and females at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users tolerate biases in race and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

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

Senior officers were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study found the system was had a higher probability to produce incorrect matches for images depicting women, 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 possible hits be increased to a level where the disparity was significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the number of searches that yielded possible identifications from over half to a just under 15%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the recent NPL study found the system could generate false positives for Black women nearly a hundred times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “Our evaluation identified that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the effect of the brief increase to the system's confidence threshold, the police records note: “The change significantly reduces the impact of bias across protected characteristics of race, generation and gender but had a significant negative impact on police efficiency”. The papers further note that police units complained that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration through equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations show once again that the pledges to combat discrimination policing has undertaken via the race action plan are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the study with utmost gravity and we have implemented changes. A new algorithm has been externally evaluated and procured, 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 gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be pursued without specialist personnel meticulously examining the output.”