British Police Forces Campaign to Use Biased Face Scanning Technology

Police forces across the United Kingdom effectively campaigned to use a facial recognition system known to be discriminatory against females, young people, and individuals from 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 carry out retrospective facial recognition searches. This procedure entails comparing a “probe image” of a suspect against a repository of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The UK interior ministry conceded last week that the technology was flawed. This acknowledgment followed a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The Home Office stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users accept biases in ethnicity and sex. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was intended to address the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to produce incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the national police leadership body ordered that the confidence threshold required for potential matches be increased to a level where the disparity was greatly diminished.

However, this decision was reversed the following month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting cut the proportion of queries that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest NPL study found the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry commented on these results: “Our evaluation found 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 effect of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, age and sex but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of questionable value”.

Broader Rollout Plans

Meanwhile, the government has opened a ten-week consultation on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little discussion through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“These revelations show yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are failing to be integrated into wider practice. Our reports have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and faulty information gathering continue to exist.

“Any use of facial recognition must meet rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson stated: “We treat the conclusions of the report seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“Our priority is ensuring public safety. This revolutionary tool will support police to put criminals and rapists behind bars. There is human involvement in every step of the process and no arrest or charge would be pursued without trained officers carefully reviewing the output.”