UK Police Forces Lobbied to Employ Discriminatory Facial Recognition Technology

Law enforcement agencies across the UK effectively campaigned to use a facial recognition system known to be biased against women, youths, and individuals from ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

UK forces use 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 database of more than 19 million custody photos to identify potential matches.

Admitted Bias

The Home Office admitted last week that the system was biased. This acknowledgment came after a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than Caucasian males. The Home Office stated it “had acted on the findings”.

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

Long-Standing Problem

Internal documents show that this discriminatory flaw has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse 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 laboratory study found the system was had a higher probability to suggest false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a level where the bias was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was generating fewer “useful lines of inquiry”. NPCC documents show the stricter setting cut the proportion of queries that yielded potential matches from 56% to a just under 15%.

Severe Disparities

Although the authorities declined to specify what setting is currently used, the recent NPL study discovered the system could produce incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The Home Office stated on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the effect of the temporary raise to the system's confidence threshold, the police records state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a significant negative impact on police efficiency”. The papers further note that forces complained that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has opened a two-and-a-half-month consultation on its plans to widen the use of biometric scanning systems. The minister for police Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the independent scrutiny and oversight board for the national policing equality strategy, commented: “There was scant consideration in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“These revelations demonstrate once again that the anti-racism commitments policing has made through the equality initiative are not being translated into wider practice. Independent assessments have warned that innovative tools are being implemented in a context where racial disparities, weak scrutiny and faulty information gathering already persist.

“All deployment of facial recognition must adhere to rigorous official guidelines, be subject to external review, and prove it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative said: “We treat the conclusions of the report with utmost gravity and we have already taken action. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in every step of the procedure and no arrest or charge would be pursued without specialist personnel carefully reviewing the output.”