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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a more accurate version produced fewer investigative leads.

The Technology in Practice

British police utilize the police national database (PND) to conduct searches using historical face recognition. This procedure entails matching a “probe image” of a person of interest against a repository of over 19 million custody photos to find possible hits.

Admitted Bias

The Home Office conceded last week that the system was flawed. This acknowledgment followed a review by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The Home Office said it “took steps on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users accept discrimination in race and gender. Convenience is a weak argument for disregarding basic freedoms.”

Known Issue

Official papers reveal that this bias has been known about for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 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 accuracy setting required for potential matches be raised to a point where the bias was significantly reduced.

However, this directive was overturned the following month following complaints from police that the adjusted system was producing a lower number of “investigative leads”. Internal records indicate the higher threshold cut the proportion of queries that yielded possible identifications from over half to a mere 14%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the latest NPL study discovered the system could produce false positives for women of Black heritage almost 100 times more frequently than for white women at certain settings.

The Home Office commented on these results: “The testing found that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the effect of the brief increase to the system's confidence threshold, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents add that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. The minister for police the relevant minister has described the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, commented: “There was very little consideration through race action plan meetings of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken through the race action plan are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“Any use of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the findings of the report seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in every step of the process and no further action would be taken without trained officers carefully reviewing the output.”