UK Law Enforcement Agencies Campaign to Use Discriminatory Facial Recognition Technology

Law enforcement agencies across the UK successfully lobbied to use a facial recognition system known to be discriminatory against females, young people, and members of ethnic minority groups, after complaining that a more accurate version produced a reduced number of potential suspects.

The Technology in Practice

UK forces utilize the national police database to carry out retrospective facial recognition searches. This process entails comparing a “probe image” of a person of interest against a repository of over 19 million custody photos to identify potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This admission came after a review by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and women at much greater frequency than white men. The ministry said it “took steps on the findings”.

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

Known Issue

Official papers show that this bias has been known about for more than a year. Furthermore, police forces lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The government-ordered laboratory study found the system was had a higher probability to produce incorrect matches for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In response, the national police leadership body mandated that the confidence threshold required for potential matches be increased to a point where the disparity was significantly reduced.

However, this directive was overturned the following month after forces complained that the modified technology was generating fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the proportion of queries resulting in possible identifications from over half to a mere 14%.

Profound Inequalities

Although the authorities declined to specify what threshold is currently used, the recent NPL study discovered the system could produce false positives for Black women almost 100 times more often than for Caucasian women at specific configurations.

The Home Office commented on these results: “The testing identified that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the police records note: “The change significantly reduces the effect of bias across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on operational effectiveness”. The documents add that police units argued that “a once effective tactic returned outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a ten-week consultation on its plans to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration 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 anti-racism commitments the police has made through the equality initiative are not being translated into wider practice. Our reports have cautioned that new technologies are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

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

Home Office Response

A government representative stated: “The Home Office treat the conclusions of the report seriously and we have already taken action. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“Our priority is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no further action would be taken without trained officers meticulously examining the results.”