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Police forces across the UK successfully lobbied to use a face scanning system known to be biased against women, youths, and individuals from minority ethnic backgrounds, following complaints that a more accurate version generated a reduced number of investigative leads.

The Technology in Practice

British police utilize the national police database to conduct searches using historical face recognition. This procedure entails matching a reference photograph of a suspect against a repository of more than 19 million custody photos to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the system was flawed. This acknowledgment followed a review by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at significantly higher rates than Caucasian males. The Home Office said it “had acted on the findings”.

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

Long-Standing Problem

Official papers reveal that this bias has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Police bosses were informed of the system's bias in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce false positives for photos of females, Black people, and those under 40 years old.

A Reversed Decision

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

However, this decision was reversed the next month after forces complained that the modified technology was producing a lower number of “useful lines of inquiry”. NPCC documents show the higher threshold reduced the proportion of queries resulting in potential matches from 56% to a just under 15%.

Profound Inequalities

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

The ministry stated on these findings: “The testing found that in a limited set of circumstances the software is has a greater tendency to incorrectly include some population segments in its match reports.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the impact of bias across legally safeguarded attributes of race, generation and sex but had a significant negative impact on operational effectiveness”. The documents further note that forces argued that “a once effective tactic now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its proposals to expand the use of biometric scanning systems. Policing minister the relevant minister has labeled the technology as the “most significant advance 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, commented: “There was very little consideration through equality strategy sessions of the technology deployment despite obvious cross-over with the strategy's goals.

“These revelations show yet again that the anti-racism commitments the police has made through the equality initiative are failing to be integrated into broader operations. Independent assessments have warned that new technologies are being implemented in a landscape where ethnic inequalities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must meet strict national standards, be subject to external review, and demonstrate it reduces rather than compounds ethnic bias.”

Home Office Response

A Home Office spokesperson said: “We treat the findings of the report 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 subject to evaluation.

“Our priority is protecting the public. This gamechanging technology will support officers to apprehend and prosecute offenders. There is officer review in every step of the procedure and no further action would be taken without specialist personnel carefully reviewing the results.”