British Law Enforcement Agencies Campaign to Use Biased Facial Recognition Systems

Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system known to be discriminatory against females, young people, and members of minority ethnic backgrounds, following complaints that a less biased 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 procedure involves comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was biased. This admission came after a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users accept biases in race and gender. 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, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The government-ordered NPL review found the system was had a higher probability to suggest incorrect matches for photos of women, Black people, and those aged 40 and under.

A Reversed Decision

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

However, this decision was reversed the following month after forces complained that the adjusted system was generating a lower number of “useful lines of inquiry”. Internal records indicate the stricter setting cut the number of queries resulting in potential matches from over half to a just 14%.

Severe Disparities

Although the authorities refused to say what threshold is currently used, the latest independent review found the system could generate incorrect matches for women of Black heritage almost 100 times more often than for white women at certain settings.

The Home Office commented on these findings: “Our evaluation found that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the police records state: “The change significantly reduces the effect of bias across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The documents further note that police units argued that “a once effective tactic now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to widen the use of biometric scanning systems. The minister for police the relevant minister has described the tool 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 police race action plan, commented: “We observed very little discussion in equality strategy sessions of the technology deployment despite clear relevance with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has made via the race action plan are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

“All deployment of facial recognition must meet strict national standards, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Official Statement

A government representative stated: “We treat the findings of the report seriously and we have already taken action. A updated software has been externally evaluated and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be taken without trained officers carefully reviewing the output.”