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

The Technology in Practice

British police use the national police database to carry out searches using historical face recognition. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched Black and Asian people and women at much greater frequency than white men. The Home Office said it “had acted on the findings”.

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

Known Issue

Internal documents show that this discriminatory flaw has been known about for more than a year. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to produce false positives for photos of women, individuals of Black ethnicity, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a level where the disparity was significantly reduced.

However, this directive was overturned the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. Internal records indicate the stricter setting cut the proportion of queries resulting in possible identifications from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the recent independent review discovered the system could generate false positives for women of Black heritage almost 100 times more often than for Caucasian women at certain settings.

The ministry stated on these findings: “Our evaluation found that in a specific scenarios the algorithm is more likely to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, age and sex but had a substantially detrimental effect on police efficiency”. The papers further note that police units argued that “a once effective tactic now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the police race action plan, said: “There was scant consideration in equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“This disclosure show once again that the pledges to combat discrimination the police has undertaken through the equality initiative are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must adhere to strict national standards, be subject to external review, and prove it reduces rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We treat the findings of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“Our priority is protecting the public. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the procedure and no further action would be taken without trained officers carefully reviewing the results.”