🔗 Share this article

Law enforcement agencies across the UK successfully lobbied to use a facial recognition system acknowledged as discriminatory against women, young people, and individuals from minority ethnic backgrounds, following complaints that a less biased version generated fewer investigative leads.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This process entails matching a reference photograph of a person of interest against a repository of more than 19 million custody photos to find potential matches.

Acknowledged Discrimination

The Home Office conceded last week that the system was biased. This admission followed a study by the government's National Physical Laboratory determined it misidentified 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”.

“It prompts the issue of whether facial recognition only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding fundamental rights.”

Known Issue

Official papers reveal that this bias has been recognized for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the algorithmic discrimination in late 2024. The government-ordered laboratory study concluded 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 response, the national police leadership body ordered that the confidence threshold required for potential matches be raised to a level where the disparity was greatly diminished.

However, this directive was reversed the next month following complaints from police that the modified technology was producing fewer “investigative leads”. NPCC documents show the higher threshold cut the proportion of queries that yielded possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what setting is currently used, the recent independent review found the system could generate incorrect matches for women of Black heritage nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office commented on these findings: “The testing identified that in a specific scenarios the algorithm is more likely 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: “The change significantly reduces the impact of bias across protected characteristics of race, generation and gender but had a substantially detrimental effect on police efficiency”. The documents add that police units argued that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its plans to expand the use of facial recognition technology. Policing minister Sarah Jones has described the technology as the “biggest breakthrough since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, chair of the advisory panel for the police race action plan, said: “We observed scant discussion in equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the anti-racism commitments policing has made through the race action plan are not being translated into wider practice. Independent assessments have warned that new technologies are being implemented in a landscape where racial disparities, weak scrutiny and poor data collection already persist.

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

Home Office Response

A government representative said: “We treat the conclusions of the report with utmost gravity and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist officers to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be pursued without trained officers meticulously examining the results.”