Sainsbury's
Sainsbury's is a notable user of Facewatch. This means that in certain branches, the cameras perform facial recognition on every customer in the shop. Sainsbury's have announced their intent to accelerate the aggressive roll-out of this technology. Legally, these shops are required to have a notice in the window disclosing the use of facial recognition, but these signs can be discreet and easy to miss.
This is not a complete list! If you know of a branch using facial recognition that is not listed here, please add it!
Known locations
Deptford
The Sainsbury's Local right outside of Deptford railway station.
East Dulwich
Elephant and Castle
This branch uses Facewatch and has received news coverage about an innocent customer being wrongfully identified as a criminal.