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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against females, youths, and individuals from ethnic minority groups, following complaints that a more accurate version generated fewer investigative leads.

How the System Works

British police use the national police database to carry out retrospective facial recognition searches. This procedure involves comparing a “probe image” of a person of interest against a database of over 19 million custody photos to identify possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the system was flawed. This admission came after a review by the government's National Physical Laboratory found it misidentified Black and Asian people and women at significantly higher rates than white men. The ministry stated it “took steps on the findings”.

“It prompts the question of whether this technology only becomes useful if users accept discrimination in ethnicity and gender. Operational ease is a poor argument for disregarding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was designed to address the problem.

Police bosses were informed of the algorithmic discrimination in late 2024. The Home Office-commissioned NPL review concluded the system was more likely to produce false positives for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for possible hits be raised to a level where the bias was greatly diminished.

However, this decision was overturned the following month following complaints from police that the modified technology was producing a lower number of “investigative leads”. Internal records indicate the stricter setting reduced the number of queries that yielded potential matches from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what threshold is currently used, the latest NPL study discovered the system could generate incorrect matches for Black women nearly a hundred times more often than for white women at specific configurations.

The Home Office commented on these results: “Our evaluation identified that in a specific scenarios the algorithm is more likely to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the brief increase to the system's accuracy setting, the police records note: “The change significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and gender but had a significant negative impact on police efficiency”. The documents further note that police units argued that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has described the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, commented: “We observed very little consideration through equality strategy sessions of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments the police has undertaken via the equality initiative are failing to be integrated into broader operations. Our reports have warned that innovative tools are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of this technology must meet strict national standards, be independently scrutinised, and prove it diminishes rather than compounds racial disparity.”

Home Office Response

A Home Office spokesperson said: “We takes 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 early next year and will be undergo evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the procedure and no further action would be taken without trained officers carefully reviewing the output.”