🔗 Share this article

Police forces across the United Kingdom effectively campaigned to use a face scanning system acknowledged as discriminatory against women, young people, and members of ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

How the System Works

British police use the national police database to conduct searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a repository of over 19 million custody photos to find possible hits.

Admitted Bias

The Home Office admitted last week that the system was flawed. This admission followed a study by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for more than a year. Furthermore, police forces lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

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

However, this directive was overturned the next month after forces complained that the modified technology was generating fewer “investigative leads”. Internal records indicate the stricter setting cut the number of queries resulting in potential matches from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is currently used, the recent NPL study found the system could generate false positives for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The Home Office stated on these findings: “The testing identified that in a limited set of circumstances the algorithm is more likely to incorrectly include 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 NPCC documents note: “The change greatly lessens the effect of discrimination across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a previously useful tool now delivered outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to expand the use of biometric scanning systems. The minister for police the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, head of the advisory panel for the police race action plan, said: “There was very little discussion in equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“This disclosure demonstrate once again that the pledges to combat discrimination the police has undertaken via the race action plan are not being translated into broader operations. Independent assessments have warned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and faulty information gathering continue to exist.

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

Home Office Response

A government representative stated: “We takes the conclusions of the study with utmost gravity and we have already taken action. A updated software has been independently tested 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 apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be taken without trained officers carefully reviewing the output.”