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Law enforcement agencies across the United Kingdom successfully lobbied to deploy a face scanning system acknowledged as biased against women, young people, and members of ethnic minority groups, following complaints that a less biased version produced a reduced number of investigative leads.

How the System Works

UK forces use the national police database to conduct searches using historical face recognition. This process involves matching a reference photograph of a person of interest against a repository of over 19 million custody photos to find potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This acknowledgment came after a study by the National Physical Laboratory (NPL) found it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the question of whether this technology only becomes useful if users accept discrimination in race and sex. Operational ease is a poor argument for disregarding fundamental rights.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement argued to overturn an initial decision that was designed to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In reaction, the national police leadership body mandated that the accuracy setting required for potential matches be raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. NPCC documents indicate the higher threshold cut the number of searches that yielded potential matches from 56% to a just under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest independent review found the system could generate false positives for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

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

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the impact of bias across protected characteristics of race, age and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces complained that “a previously useful tool now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has launched a ten-week public review on its plans to widen 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

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, said: “We observed very little consideration through race action plan meetings of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments policing has made through the race action plan are not being translated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “We takes the findings of the report seriously and we have implemented changes. A updated software has been externally evaluated and procured, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no arrest or charge would be taken without specialist personnel meticulously examining the output.”