South Wales Police carried out the U.K.’s first arrest using facial recognition, Ars Technica UK reported.

The arrest using automatic facial recognition was made on May 31 and was not related to the Champions League final. It’s unclear whether the apprehension was due to authorities testing the technology prior to the match.

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International Business Times has reached out to South Wales Police regarding the arrest. The department said in a statement on Tuesday there was “a very low number of arrests over the period of the festival including match day.”

South Wales Police announced a partnership last month with NEC to pilot facial recognition technology during the Champions League finals week in Cardiff during late May and early June. South Wales Police announced it would be the first in the U.K. to use facial recognition technology at a major sporting event.

The technology allowed authorities to monitor the movement of people at strategic locations in and around the city center. Using a number of camera positions, police would be able to identify those who are on predetermined watch lists, which includes people suspected of criminality, missing individuals and persons of interest.  

“Like fingerprinting, facial recognition is a form of identification that allows a computer to quickly match similar faces based on facial features,” Inspector Scott Lloyd, who leads the facial recognition team, said in a statement May 22.

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South Wales Police said the facial recognition technology can be used in both public safety and national security environments, such as identifying people during a disturbance or in places like Cardiff Airport and Welsh sports stadiums.

“This facial recognition technology will enable us to search, scan and monitor images and video of suspects against offender databases, leading to the faster and more accurate identification of persons of interest,” Assistant Chief Constable Richard Lewis said in a statement. 

Facial Recognition Technology And Privacy

South Wales Police acknowledged facial recognition raises privacy concerns.

“We are very cognizant of concerns about privacy, and we are building in checks and balances into our methodology to reassure the public that the approach we take is justified and proportionate,” Lewis said.

He said South Wales Police have had “detailed discussions” with regulatory partners “to ensure that we are considering the wider needs in relation to the Data Protection Act and to ensure that the deployment of this technology is proportionate whilst recognizing the need to balance security and privacy.”

Facial recognition technology was used previously in the U.K. by Leicestershire Police at the Download music festival in 2015. Police used NEC’s NeoFace system to scan those entering the arena. The move sparked outrage from fans and even from the band Muse, which said police were "scanning our faces without telling us."

“What most people don’t understand is that we are photographed multiple times a day – no matter where we are in the world,” Ted Farnsworth of Helios and Matheson Analytics Inc. told International Business Times. “Privacy issues are certainly a concern when we feed images into databases, but this technology is the most effective tool in solving crimes with a known attacker on the loose. Most law enforcement departments don't have the resources or manpower to track known dangerous individuals in the system.”

Farnsworth said successful arrests using facial recognition will lead to the increased use of the technology at more venues in the future. He sees the technology becoming more efficient too.

“In future versions of algorithms, law enforcement will be able to conduct personality profiling to gauge stress points in a suspect’s face and likelihood of a second offense,” said Farnsworth. “It’s the same behavior analysis law enforcement uses during one-on-one interviews with suspects, but it will be done in real-time through artificial intelligence before known threats have a chance to strike.”