In uk.d-i-y, wrote:

........................... Maybe (this is quite common) it's got all
three earth wires, I mean Circuit Protective Conductors, twisted together
in one piece of green-and-yellow sleeving? If so, you're basically in
OK shape ...

I forgot to add at this point, "provided that all three conductors
carry on to the end and are all clamped together under the screw in
your fitting": it's *not* remotely safe practice for them to be just
twisted together and to have just one extending into the fitting.