Lighting circuit with no CPC, fail???

[shagbite]

You'll probably find that the conduit has been used as an earth. If the loop test is satisfactory and there is no obvious degradation (which I doubt) then the installation must only be as good as the regs, probably 13th or14th, defined at the time of installation. I think a good visual inspection will prove that this installation needs rewiring, put away your instruments and use your common sense.

the op has already said there was no conduit being used as cpc.