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Law enforcement agencies across the United Kingdom effectively campaigned to deploy a face scanning system known to be biased against females, young people, and individuals from ethnic minority groups, after complaining that a less biased version generated fewer potential suspects.

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 “probe image” of a suspect against a database of over 19 million custody photos to find possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was biased. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. The ministry said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate discrimination in race and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

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

Senior officers were informed of the algorithmic discrimination in September 2024. The government-ordered NPL review found the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this decision was reversed the following month following complaints from police that the modified technology was producing fewer “investigative leads”. Internal records show the higher threshold cut the number of searches that yielded potential matches from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is currently used, the latest NPL study found the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for white women at certain settings.

The ministry stated on these findings: “The testing identified that in a specific scenarios the software is more likely to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Describing the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “The change significantly reduces the impact of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The documents add that forces complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a two-and-a-half-month consultation on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

Abimbola Johnson, chair of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant consideration in race action plan meetings of the facial recognition rollout despite obvious cross-over with the plan’s concerns.

“This disclosure show once again that the anti-racism commitments the police has undertaken via the race action plan are failing to be integrated into broader operations. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

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

Official Statement

A government representative said: “The Home Office treat the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, 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 procedure and no further action would be taken without specialist personnel meticulously examining the output.”