Facial recognition technology takes two main forms. The first compares an image of an unknown person (for example caught on CCTV committing a crime, reviewed after the event) against a database of facial images of people who have been arrested. All police forces use the Police National Database facial search facility.
The second form is live facial recognition (LFR), which compares images of passers-by taken from live cameras with images on a watch list (a database of suspects). Possible matches produced by LFR systems are always checked by a human operator before deciding what, if any, action to take. The Metropolitan Police Service (MPS) and South Wales Police (SWP) are piloting LFR. The pilots are important to test this technology, which has the potential to improve public safety. SWP have been carrying out trials since May 2017. MPS completed a series of ten pilots in February 2019.
Both forces have commissioned independent evaluations of their trials. Cardiff University has published its evaluation of South Wales Police’s trials between May 2017 and March 2018. Essex University will shortly be publishing their review of the Metropolitan Police Service’s trials. MPS will consider next steps in the light of this review. The Law Enforcement Facial Images and New Biometric Modalities Oversight and Advisory Board oversees the police use of LFR, the retention of custody images, and emerging new biometrics. The Board’s minutes are published on GOV.UK