According to a City of London web page, there are almost 280 traffic accidents annually in the city related to running a red light. In an effort to reduce this number, the city has installed red light cameras (RLC) at ten intersections.
Not every car is photographed. Only those cars entering the intersection after the light has turned red. Enter on a red and trigger the RLC system. Some drivers erroneously believe they exempt if they are part of a funeral procession. Not true.
When a car approaches a monitored intersection, two pictures are taken. The first photo shows the car in question immediately before entering the intersection and the second photo shows the car in the intersection.
According to the city, "Both photographs show a red traffic signal, when the photograph was taken, the length of the amber signal, how long the signal has been red and the speed of the vehicle."
The penalty for being photographed running a red light is similar to the penalty when given a ticket directly. The amount of the fine is the same $325 but being stopped by a police officer results in demerit points as well. There are no demerit points associated with a red light camera ticket. This may be because the red light ticket is issued to the owner of the car. It is not assumed the owner and the driver are the same person.