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Police forces across the United Kingdom successfully lobbied to use a face scanning system known to be discriminatory against women, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated fewer investigative leads.

How the System Works

British police utilize the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a suspect against a repository of over 19 million mugshots to find possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined 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”.

“It prompts the issue of whether facial recognition only becomes useful if users accept discrimination in ethnicity and sex. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers show that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to produce incorrect matches for photos of females, Black people, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for potential matches be increased to a point where the disparity was greatly diminished.

However, this decision was overturned the next month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold cut the proportion of searches resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the recent NPL study found the system could produce incorrect matches for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The Home Office commented on these findings: “The testing identified that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's accuracy setting, the NPCC documents state: “The change greatly lessens the impact of discrimination across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The documents further note that police units argued that “a previously useful tool returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “There was very little consideration through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations demonstrate once again that the pledges to combat discrimination policing has made through the equality initiative are failing to be integrated into broader operations. Independent assessments have warned that innovative tools are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

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

Official Statement

A government representative said: “The Home Office treat the findings of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will support police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers meticulously examining the output.”