Lamp proving

[PJW]

Thank you very much Mr. Dorothy & PJW for the clarification.........
I got another doubt. Please clear it.
Incase the signal lamp proving is not required, how come the signaller knows about the indication?

If the signal lamp is not proved at all (e.g. For SSI the lamp is not wired into a current proved input) then the signaller will only find out that it is not illluminated is if a driver, technician or some other trackside worker notices and reports it to them)