🔗 Share this article

Law enforcement agencies across the United Kingdom effectively campaigned to deploy a facial recognition system acknowledged as biased against females, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version produced a reduced number of investigative leads.

The Technology in Practice

British police utilize the police national database (PND) to conduct retrospective facial recognition searches. This process entails matching a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The Home Office stated it “took steps on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a poor argument for overriding basic freedoms.”

Known Issue

Internal documents show that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce incorrect matches for images depicting females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body ordered that the accuracy setting required for possible hits be increased to a level where the bias was greatly diminished.

However, this directive was reversed the next month following complaints from police that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records show the higher threshold reduced the number of searches resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is now in operation, the recent independent review discovered the system could produce false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The Home Office stated on these results: “Our evaluation 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 temporary raise to the system's accuracy setting, the police records state: “This adjustment significantly reduces the impact of discrimination across protected characteristics of race, age and sex but had a substantially detrimental effect on police efficiency”. The papers add that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure show once again that the pledges to combat discrimination policing has made via the equality initiative are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

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

Official Statement

A Home Office spokesperson said: “The Home Office takes the conclusions of the study 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 further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be taken without trained officers meticulously examining the output.”