Powerline Networks Interfere With Spooks?

An anonymous reader writes "Powerline technology which ships network data over mains cables could be causing interference for spies, according to a letter from the UK's top secret listening station, GCHQ. However, the British regulator says that objections to powerline all come from radio amateurs — and a Google search reveals that the writer of the letter (which GCHQ seems to be disowning) comes from a ham."