British Police Forces Campaign to Use Biased Facial Recognition Technology

Police forces across the United Kingdom successfully lobbied to use a facial recognition system acknowledged as discriminatory against women, youths, and members of ethnic minority groups, following complaints that a more accurate version produced a reduced number of potential suspects.

The Technology in Practice

British police use the national police database to conduct retrospective facial recognition searches. This process involves comparing a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and females at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“This raises the question of whether this technology only becomes useful if users tolerate biases in race and gender. Convenience is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to address the problem.

Police bosses were informed of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review found the system was had a higher probability to suggest incorrect matches for images depicting women, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be increased to a point where the bias was greatly diminished.

However, this decision was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded possible identifications from over half to a just under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study found the system could produce incorrect matches for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office stated on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents note: “This adjustment significantly reduces the impact of discrimination across protected characteristics of ethnicity, age and sex but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool returned results of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has opened a two-and-a-half-month consultation on its proposals to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the police race action plan, commented: “There was scant consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments the police has made through the equality initiative 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 already persist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative said: “We takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has no statistically significant bias. It will be tested in the coming months and will be subject to evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is officer review in every step of the process and no further action would be taken without trained officers meticulously examining the output.”