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Police forces across the United Kingdom successfully lobbied to use a facial recognition system acknowledged as biased against females, youths, and members of ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces use the police national database (PND) to conduct searches using historical face recognition. This process entails comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This acknowledgment followed a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

“This raises the question of whether this technology only becomes effective if users tolerate discrimination in race and sex. Operational ease is a weak argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal 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 mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for images depicting females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

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

However, this decision was reversed the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. Internal records show the stricter setting cut the number of searches resulting in possible identifications from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent independent review discovered the system could generate incorrect matches for women of Black heritage almost 100 times more frequently than for Caucasian women at certain settings.

The ministry stated on these results: “The testing identified that in a limited set of circumstances the software is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the police records state: “This adjustment significantly reduces the effect of bias across protected characteristics of ethnicity, generation and sex but had a significant negative impact on operational effectiveness”. The documents add that forces argued that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month consultation on its proposals to widen 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

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, said: “There was very little discussion through equality strategy sessions of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure demonstrate once again that the anti-racism commitments the police has made via the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned 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 facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “The Home Office treat the findings of the study seriously and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support officers to apprehend and prosecute offenders. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”