The Police National Database holds more than 15 million mugshots of people. These can all be searched using the police’s facial recognition software.
Any image (whether it is a social media, or a CCTV image) can be uploaded to the system and compared against the images that are in the database.
“Facial search can be used on facial images found in fraudulently obtained documents in order to assist in identifying perpetrators,” a guide to using the system says.
The images that are uploaded should only contain one person and there must be enough pixels between the pupils for the system to work. Images uploaded are not stored in the police database.
The below document is the Home Office guide for those in the police who want to use the technology to help their investigations.