🔗 Share this article

Police forces across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against females, youths, and individuals from ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

How the System Works

UK forces utilize the police national database (PND) to carry out retrospective facial recognition searches. This process entails comparing a reference photograph of a suspect against a database of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission followed a review by the government's National Physical Laboratory found it incorrectly matched people of Black and Asian heritage and females at significantly higher rates than white men. The ministry said it “had acted on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in race and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement argued to overturn an initial decision 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 incorrect matches for photos of women, Black people, and those aged 40 and under.

A Policy U-Turn

In response, the national police leadership body ordered that the accuracy setting required for potential matches be raised to a point where the disparity was greatly diminished.

However, this decision was reversed the next month after forces complained that the adjusted system was producing fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries resulting in potential matches from 56% to a just under 15%.

Severe Disparities

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

The Home Office stated on these results: “Our evaluation found that in a specific scenarios the software is has a greater tendency to incorrectly include some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the police records note: “This adjustment significantly reduces the impact of bias across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The documents add that forces complained that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

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

Criticism from Advisors and Monitors

The chair of a police oversight board, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was very little discussion through equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations show once again that the anti-racism commitments policing has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and poor data collection continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A Home Office spokesperson said: “We takes the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and procured, which has no statistically significant bias. It will be trialled in the coming months and will be subject to further assessment.

“The foremost aim is ensuring public safety. This revolutionary tool will assist police to put criminals and rapists behind bars. There is officer review in every step of the process and no further action would be taken without specialist personnel meticulously examining the results.”