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Police forces across the UK successfully lobbied to deploy a face scanning system known to be discriminatory against women, young people, and individuals from ethnic minority groups, after complaining that a more accurate version generated a reduced number of potential suspects.

The Technology in Practice

British police use the national police database to conduct searches using historical face recognition. This process entails comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was flawed. This admission followed a study by the National Physical Laboratory (NPL) determined it incorrectly matched Black and Asian people and women at much greater frequency than Caucasian males. The ministry said it “took steps on the findings”.

“It prompts the question of whether this technology only becomes effective if users accept discrimination in race and sex. Operational ease is a poor argument for overriding fundamental rights.”

Known Issue

Internal documents reveal that this bias has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an earlier ruling that was intended to mitigate the problem.

Senior officers were informed of the system's bias in late 2024. The Home Office-commissioned laboratory study 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 Reversed Decision

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

However, this decision was reversed the next month following complaints from police that the adjusted system was producing fewer “useful lines of inquiry”. Internal records show the higher threshold reduced the proportion of queries that yielded possible identifications from 56% to a mere 14%.

Profound Inequalities

Although the Home Office and NPCC refused to say what setting is now in operation, the recent NPL study found the system could produce false positives for women of Black heritage nearly a hundred times more often than for Caucasian women at certain settings.

The Home Office commented on these results: “The testing identified that in a specific scenarios the software is has a greater tendency to wrongly flag some demographic groups in its search results.”

Operational Effectiveness vs. Bias

Describing the effect of the brief increase to the system's confidence threshold, the police records state: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of race, age and gender but had a significant negative impact on operational effectiveness”. The papers further note that forces argued that “a previously useful tool now delivered outcomes of limited benefit”.

Broader Rollout Plans

Meanwhile, the government has launched a ten-week consultation on its plans to widen the use of facial recognition technology. Policing minister the relevant minister has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, head of the advisory panel for the national policing equality strategy, said: “We observed very little discussion through race action plan meetings of the technology deployment even with clear relevance with the strategy's goals.

“This disclosure demonstrate yet again that the pledges to combat discrimination policing has undertaken through the equality initiative are not being translated into wider practice. Our reports have cautioned that innovative tools are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of this technology must meet rigorous official guidelines, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A Home Office spokesperson said: “We takes the findings of the study seriously and we have already taken action. A new algorithm has been externally evaluated and acquired, which has no statistically significant bias. It will be tested early next year and will be subject to evaluation.

“Our priority is protecting the public. This revolutionary tool will support officers to apprehend and prosecute offenders. There is human involvement in each stage of the procedure and no arrest or charge would be taken without trained officers carefully reviewing the results.”