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Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as discriminatory against women, young people, and members of ethnic minority groups, following complaints that a less biased version produced fewer investigative leads.

The Technology in Practice

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

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The Home Office stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate biases in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers show that this bias has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was more likely to suggest false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be increased to a level where the disparity was significantly reduced.

However, this decision was reversed the following month following complaints from police that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting cut the proportion of queries resulting in potential matches from over half to a mere 14%.

Severe Disparities

Although the authorities refused to say what setting is currently used, the latest NPL study discovered the system could generate incorrect matches for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office commented on these results: “Our evaluation identified that in a limited set of circumstances the algorithm is more likely to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the effect of bias across protected characteristics of race, age and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a previously useful tool now delivered results 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 Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken via the equality initiative are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of facial recognition must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson stated: “We takes the findings of the report seriously and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be undergo evaluation.

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