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Police forces across the UK successfully lobbied to use a facial recognition system known to be discriminatory against women, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of investigative leads.

The Technology in Practice

UK forces utilize the police national database (PND) to conduct retrospective facial recognition searches. This process involves comparing a “probe image” of a person of interest against a database of over 19 million mugshots to identify possible hits.

Admitted Bias

The Home Office admitted last week that the system was biased. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage 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 effective if users tolerate biases in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the system's bias in September 2024. The government-ordered NPL review concluded the system was more likely to produce false positives for images depicting women, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In response, the National Police Chiefs’ Council (NPCC) ordered that the accuracy setting required for possible hits be increased to a point where the bias was greatly diminished.

However, this decision was reversed the next month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records show the stricter setting cut the proportion of searches that yielded potential matches from over half to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what setting is currently used, the latest NPL study found the system could generate incorrect matches for Black women almost 100 times more often than for white women at specific configurations.

The Home Office commented on these results: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some demographic groups in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's confidence threshold, the police records note: “The change greatly lessens the impact of bias across protected characteristics of ethnicity, age and gender but had a substantially detrimental effect on operational effectiveness”. The papers add that forces argued that “a once effective tactic returned results of questionable value”.

Wider Implementation Proposals

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 described the technology as the “biggest breakthrough since genetic fingerprinting”.

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 consideration in race action plan meetings of the facial recognition rollout despite clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the anti-racism commitments the police has undertaken via the race action plan are not being translated into broader operations. Our reports have warned that new technologies are being implemented in a context where ethnic inequalities, weak scrutiny and poor data collection already persist.

“Any use of this technology must adhere to strict national standards, be independently scrutinised, and demonstrate it diminishes rather than exacerbates ethnic bias.”

Official Statement

A Home Office spokesperson said: “The Home Office treat the conclusions of the report seriously and we have already taken action. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be subject to further assessment.

“Our priority is protecting the public. This gamechanging technology will assist police 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.”