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Police forces across the UK effectively campaigned to deploy a face scanning system known to be biased against women, youths, and members of ethnic minority groups, following complaints that a more accurate version generated fewer investigative leads.

How the System Works

UK forces use the police national database (PND) to carry out retrospective facial recognition searches. This process entails matching a reference photograph of a person of interest against a database of more than 19 million mugshots to find possible hits.

Admitted Bias

The Home Office admitted last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“This raises the question of whether this technology only becomes useful if users accept biases in race and gender. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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 significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the stricter setting cut the proportion of searches that yielded potential matches from over half to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the latest independent review found the system could produce incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry commented on these findings: “The testing 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 police records note: “This adjustment significantly reduces the impact of bias across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its plans to widen the use of facial recognition technology. The minister for police Sarah Jones has described the tool as the “biggest breakthrough 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: “We observed scant consideration through race action plan meetings of the technology deployment even with obvious cross-over with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made via the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“Any use of facial recognition must meet strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson stated: “The Home Office takes the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be trialled early next year and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no arrest or charge would be pursued without trained officers carefully reviewing the results.”