British Police Forces Campaign to Use Discriminatory Face Scanning Technology

Police forces across the United Kingdom effectively campaigned to use a facial recognition system acknowledged as discriminatory against females, young people, and members of minority ethnic backgrounds, after complaining that a more accurate version generated a reduced number of investigative leads.

How the System Works

UK forces use the national police database to carry out searches using historical face recognition. This process entails matching a “probe image” of a person of interest against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry conceded last week that the system was flawed. This admission came after a study by the government's National Physical Laboratory determined it misidentified people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept biases in race and sex. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been known about for more than a year. Furthermore, police forces argued to overturn an earlier ruling that was intended to address the problem.

Senior officers were informed of the system's bias in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to suggest false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

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

However, this directive was reversed the next month following complaints from police that the adjusted system was producing fewer “investigative leads”. NPCC documents show the stricter setting reduced the number of queries that yielded possible identifications from over half to a just under 15%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is currently used, the latest independent review found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for white women at specific configurations.

The ministry stated on these results: “The testing found that in a specific scenarios the software is more likely to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The papers further note that police units argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister Sarah Jones 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, commented: “There was very little consideration through equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has made via the race action plan are not being translated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“Any use of this technology must adhere to rigorous official guidelines, be independently scrutinised, and prove it reduces rather than exacerbates ethnic bias.”

Official Statement

A government representative said: “We treat the conclusions of the report seriously and we have implemented changes. A new algorithm has been externally evaluated and procured, which has no statistically significant bias. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is protecting the public. This gamechanging technology will assist police to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be pursued without trained officers carefully reviewing the output.”