I've been involved in a discussion in a UK amateur group about the possibility of neutral faults causing hazards of the protective earth (PE) getting a high voltage. Seems they use a type of wiring called PME or TN-C-S where a single conductor is used for neutral and PE with multiple earth connections.
The problem with this method is that a break in the combined protective earth/neutral (PEN) line would leave homes with a poor or no earth connection which can have an elevated voltage on the PE line.
I believe this is what we commonly have in the US. The PE is supplemented with a bond between PE and a water pipe or similar ground, but it appears even water pipes from the street are using plastic now, so there are fewer ways to get a solid ground connection.
A house wide GFCI won't protect against this problem because the current would still flow in the neutral line back to the point where it is bonded to the PE which should be before the GFCI. I was thinking a simple voltage detection on the PE line of a home relative to even a poor ground (separate from the PEN) should suffice for triggering a protective device that could be built into the main breaker for the house. It should be a very simple circuit potentially without active devices.