At the risk of doing oneself an extreme nasty, I wonder if one
could couple the RF into the national Grid by having a coupling
coil a few feet below the dangling 400kV cables?

(Obviously not a direct connection beacuse that is specifically
forbidden in Brit licensing laws :-) )


However, ISTR from 40 years ago working on the automation of
the Brit National Grid that pilot protection operates on LF somewhere
so perhaps there would be a danger to the grid itself?

(Pilot protection - send RF along the cable, and if it doesn't arrive
at the other end, then wire must have broken)