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Police forces across the UK successfully lobbied to use a face scanning system known to be discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated fewer investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a database of over 19 million mugshots to identify possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This acknowledgment followed a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“This raises the question of whether facial recognition only becomes effective if users tolerate discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to address the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered laboratory study found the system was more likely to suggest false positives for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for potential matches be raised to a point where the bias was significantly reduced.

However, this directive was reversed the next month following complaints from police that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents indicate the higher threshold reduced the proportion of searches that yielded potential matches from 56% to a mere 14%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the latest independent review found the system could generate false positives for women of Black heritage almost 100 times more frequently than for Caucasian women at specific configurations.

The ministry commented on these results: “Our evaluation found that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's accuracy setting, the police records note: “This adjustment greatly lessens the effect of discrimination across protected characteristics of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that police units argued that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant consideration through race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has made via the race action plan are failing to be integrated into wider practice. Our reports have warned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “The Home Office treat the conclusions of the study with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be tested in the coming months and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is human involvement in every step of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the results.”