Theres a pretty simple way to find out for yourself what the Fire Authorities views are on this! But who has carried out the fre risk assessment of the common areas and what is their view?
Certainly current guidance is to provide emergency escape lighting in the escape routes. In the old days - probably if the building was designed to the old CP3 Chapter 4 part 1 "Precautions against Fire- Flats and Maisonettes in blocks over two storeys" emergency escape lighting as we know it would not have been provided, but the requirement would have been for separate, protected circuits dedicated and direct from the main dis board, automatic time controls, and if the staircase had no borrowed lighting the circuits feeding the stairs should de separated from the circuits feeding the corridors. Very often such cables were buried in a small conduit and buried deep in the concrete or plaster of the building.
Now any such wiring,even if still installed and maintained to that standard will be about 40 years old, as it is reviewed there is a duty in the Fire Safety Order to "adapt to technical Progress" - ie consider applying current best practice as per the current standards. If the wiring has been replaced it more than likely does not have the protection it ussed to enjoy, and with modern wiring regs splitting phases across floors etc may make such arrangements very difficult to re-instate.