UK Police Forces Campaign to Employ Biased Facial Recognition Technology

Law enforcement agencies across the UK effectively campaigned to deploy a facial recognition system known to be biased against females, young people, and individuals from minority ethnic backgrounds, after complaining that a less biased version produced a reduced number of investigative leads.

The Technology in Practice

UK forces use the police national database (PND) to conduct retrospective facial recognition searches. This process involves matching a reference photograph of a person of interest against a repository of over 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The Home Office admitted last week that the system was flawed. This admission came after a study by the government's National Physical Laboratory determined it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The ministry said it “had acted on the findings”.

“It prompts the issue of whether this technology only becomes useful if users accept biases in ethnicity and sex. Operational ease is a poor argument for overriding basic freedoms.”

Known Issue

Official papers show that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review found the system was more likely to suggest false positives for images depicting females, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be increased to a level where the disparity was significantly reduced.

However, this decision was overturned the following month after forces complained that the modified technology was producing fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the number of searches resulting in possible identifications from over half to a mere under 15%.

Profound Inequalities

Although the authorities refused to say what setting is now in operation, the latest NPL study discovered the system could generate incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The ministry stated on these results: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a significant negative impact on operational effectiveness”. The documents add that police units complained that “a previously useful tool now delivered results of questionable value”.

Broader Rollout Plans

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 Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, said: “There was very little discussion in equality strategy sessions of the facial recognition rollout even with obvious cross-over with the plan’s concerns.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken via the race action plan are failing to be integrated into broader operations. Independent assessments have cautioned that new technologies are being rolled out in a context where ethnic inequalities, inadequate oversight and faulty information gathering continue to exist.

“Any use of this technology must meet strict national standards, be subject to external review, and demonstrate it reduces rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “The Home Office treat the findings of the study seriously and we have implemented changes. A updated software has been independently tested and procured, which has no statistically significant bias. It will be tested in the coming months and will be undergo further assessment.

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