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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, after complaining that a less biased version generated fewer potential suspects.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This procedure involves comparing a reference photograph of a person of interest against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes effective if users tolerate discrimination in race and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

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

Police bosses 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 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 confidence threshold required for possible hits be increased to a point where the disparity was greatly diminished.

However, this directive was overturned the following month after forces complained that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of searches that yielded potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what setting is now in operation, the latest NPL study found the system could produce 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: “Our evaluation found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change greatly lessens the effect of bias across protected characteristics of ethnicity, generation and sex but had a significant negative impact on police efficiency”. The papers add that police units argued that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the police race action plan, said: “We observed scant consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the plan’s concerns.

“This disclosure show yet again that the pledges to combat discrimination the police has undertaken through the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We takes the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be trialled in the coming months and will be undergo further assessment.

“Our priority 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 carefully reviewing the output.”