🔗 Share this article

Police forces across the United Kingdom successfully lobbied to deploy a facial recognition system acknowledged as biased against females, youths, and members of ethnic minority groups, after complaining that a less biased version generated fewer investigative leads.

How the System Works

British police use the national police database to carry out searches using historical face recognition. This process entails comparing a reference photograph of a suspect against a database of over 19 million custody photos to identify possible hits.

Admitted Bias

The Home Office admitted last week that the technology was flawed. This admission came after a review by the government's National Physical Laboratory determined it incorrectly matched Black and Asian people and women at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users accept biases in ethnicity and sex. Operational ease is a poor argument for overriding basic freedoms.”

Long-Standing Problem

Internal documents reveal that this discriminatory flaw has been known about for over twelve months. Furthermore, law enforcement argued to overturn an earlier ruling that was designed to mitigate the problem.

Senior officers were informed of the system's bias in September 2024. The government-ordered NPL review found the system was more likely to suggest false positives for photos of females, Black people, 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 potential matches be increased to a point where the bias was significantly reduced.

However, this directive was overturned the following month following complaints from police that the modified technology was generating fewer “investigative leads”. NPCC documents indicate the higher threshold reduced the proportion of queries that yielded potential matches from over half to a mere under 15%.

Profound Inequalities

Although the authorities declined to specify what setting is currently used, the latest NPL study discovered the system could generate false positives for Black women nearly a hundred times more frequently than for Caucasian women at certain settings.

The Home Office stated on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to incorrectly include some population segments in its match reports.”

Balancing Utility and Fairness

Describing the impact of the temporary raise to the system's accuracy setting, the NPCC documents note: “This adjustment significantly reduces the effect of discrimination across protected characteristics of race, age and sex but had a significant negative impact on police efficiency”. The documents add that forces argued that “a previously useful tool now delivered results of questionable value”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its proposals to expand the use of facial recognition technology. Policing minister the relevant minister has labeled the technology as the “most significant advance since genetic fingerprinting”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “We observed very little discussion through equality strategy sessions of the technology deployment even with obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination policing has made via the race action plan are not being translated into broader operations. Our reports have cautioned that innovative tools are being implemented in a context where racial disparities, inadequate oversight and poor data collection continue to exist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it diminishes rather than exacerbates racial disparity.”

Official Statement

A Home Office spokesperson said: “We treat the conclusions of the study with utmost gravity and we have implemented changes. A new algorithm has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested early next year and will be undergo further assessment.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in each stage of the process and no further action would be taken without trained officers carefully reviewing the results.”