🔗 Share this article

Police forces across the UK effectively campaigned to deploy a face scanning system acknowledged as discriminatory against females, young people, and individuals from minority ethnic backgrounds, following complaints that a less biased version produced fewer potential suspects.

The Technology in Practice

British police utilize the national police database to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

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

“It prompts the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned laboratory study concluded the system was more likely to produce incorrect matches for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be raised to a level where the disparity was significantly reduced.

However, this decision was overturned the next month following complaints from police that the adjusted system was producing a lower number of “useful lines of inquiry”. NPCC documents show the stricter setting cut the number of queries resulting in possible identifications from 56% to a just 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is now in operation, the recent NPL study found the system could produce false positives for Black women almost 100 times more often than for Caucasian women at specific configurations.

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

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment greatly lessens the effect of bias across legally safeguarded attributes of race, generation and sex but had a substantially detrimental effect on police efficiency”. The documents further note that police units complained that “a once effective tactic returned results of questionable value”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. Policing minister the relevant minister has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “We observed scant discussion in race action plan meetings of the facial recognition rollout despite clear relevance with the plan’s concerns.

“This disclosure show yet again that the anti-racism commitments the police has made through the race action plan are not being translated into wider practice. Our reports have warned that innovative tools are being rolled out in a landscape where ethnic inequalities, weak scrutiny and poor data collection already persist.

“All deployment of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than compounds racial disparity.”

Official Statement

A government representative said: “The Home Office treat the findings of the report with utmost gravity and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to further assessment.

“The foremost aim is protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without specialist personnel meticulously examining the output.”