British Police Forces Lobbied to Employ Biased Facial Recognition Technology

Law enforcement agencies across the UK successfully lobbied to use a face scanning system known to be biased against women, young people, and individuals from ethnic minority groups, following complaints that a less biased version generated a reduced number of potential suspects.

The Technology in Practice

British police use the police national database (PND) to conduct searches using historical face recognition. This procedure involves comparing a reference photograph of a suspect against a database of more than 19 million mugshots to identify potential matches.

Admitted Bias

The UK interior ministry conceded last week that the technology was biased. This acknowledgment came after a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The ministry stated it “had acted on the findings”.

“It prompts the question of whether facial recognition only becomes useful if users tolerate discrimination in ethnicity and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Long-Standing Problem

Internal documents show that this bias has been known about for more than a year. Furthermore, law enforcement argued to overturn an earlier ruling that was intended to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The Home Office-commissioned NPL review concluded the system was more likely to produce false positives for photos of females, Black people, and those aged 40 and under.

A Policy U-Turn

In reaction, the national police leadership body ordered that the accuracy setting required for potential matches be increased to a level where the bias was significantly reduced.

However, this decision was overturned the next month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the higher threshold cut the proportion of searches that yielded possible identifications from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the recent independent review discovered the system could produce incorrect matches for Black women nearly a hundred times more often than for white women at specific configurations.

The ministry stated on these results: “Our evaluation found that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some demographic groups in its search results.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment greatly lessens the effect of discrimination across legally safeguarded attributes of race, age and gender but had a substantially detrimental effect on police efficiency”. The documents further note that police units argued that “a once effective tactic now delivered results of questionable value”.

Broader Rollout Plans

Meanwhile, the UK administration has opened a ten-week consultation on its proposals to widen the use of biometric scanning systems. The minister for police the relevant minister has labeled the tool as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the independent scrutiny and oversight board for the police race action plan, commented: “There was very little discussion through equality strategy sessions of the facial recognition rollout even with clear relevance with the strategy's goals.

“This disclosure show yet again that the pledges to combat discrimination the police has made through the equality initiative are not being translated into wider practice. 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 rigorous official guidelines, be subject to external review, and demonstrate it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative said: “The Home Office takes the conclusions of the report seriously and we have already taken action. A updated software has been externally evaluated and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo further assessment.

“Our priority is protecting the public. This revolutionary tool will support officers to put criminals and rapists behind bars. There is human involvement in each stage of the process and no further action would be pursued without specialist personnel meticulously examining the results.”