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Law enforcement agencies across the UK successfully lobbied to deploy a face scanning system known to be discriminatory against females, youths, and individuals from ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

How the System Works

UK forces use the national police database to carry out searches using historical face recognition. This process entails matching a reference photograph of a person of interest against a database of more than 19 million custody photos to find possible hits.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This admission followed a study by the National Physical Laboratory (NPL) found it misidentified Black and Asian people and women at much greater frequency than white men. The Home Office said it “took steps on the findings”.

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

Long-Standing Problem

Internal documents reveal that this bias has been known about for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned NPL review concluded the system was had a higher probability to produce false positives for images depicting women, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the confidence threshold required for possible hits be raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the modified technology was generating a lower number of “investigative leads”. NPCC documents indicate the stricter setting cut the number of queries resulting in possible identifications from 56% to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest independent review found the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The Home Office stated 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

Outlining the effect of the temporary raise to the system's accuracy setting, the NPCC documents note: “The change significantly reduces the impact of bias across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The documents add that forces argued that “a once effective tactic returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month public review on its proposals to widen the use of facial recognition technology. The minister for police the relevant minister has labeled the tool as the “most significant advance 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: “We observed scant discussion through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has undertaken via the race action plan are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a context where racial disparities, weak scrutiny and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office treat the findings of the study seriously and we have implemented changes. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be trialled in the coming months and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is officer review in each stage of the process and no further action would be pursued without specialist personnel carefully reviewing the results.”