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Police forces across the UK successfully lobbied to use a face scanning system known to be discriminatory against women, youths, and individuals from minority ethnic backgrounds, after complaining that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the national police database to conduct searches using historical face recognition. This procedure involves comparing a “probe image” of a person of interest against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This acknowledgment followed a study by the National Physical Laboratory (NPL) found it incorrectly matched Black and Asian people and females at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes effective if users tolerate discrimination in race and gender. Convenience is a weak argument for overriding basic freedoms.”

Long-Standing Problem

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

Police bosses were informed of the system's bias in September 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for photos of females, individuals of Black ethnicity, and those under 40 years old.

A Reversed Decision

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

However, this directive was reversed the following month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the higher threshold cut the proportion of searches that yielded potential matches from over half to a just 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent independent review found the system could generate incorrect matches for Black women nearly a hundred times more frequently than for Caucasian women at certain settings.

The ministry stated on these findings: “The testing found that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents state: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on police efficiency”. The papers add that police units complained that “a previously useful tool now delivered results of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the police race action plan, commented: “We observed scant discussion in race action plan meetings of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has undertaken through the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that new technologies are being implemented in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson stated: “We takes the findings of the study with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This gamechanging technology will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without trained officers carefully reviewing the output.”