The twisted pair pendant cords, usually with each conductor individually cotton covered, used to be very common in England too, as did plain PVC-insulated twisted pair for radios and bedside lamps.
New rules in the mid 1970s, however, required cords to be double insulated, so they've gradually disappeared. I still see some old pendants fitted with the twisted pairs from time to time.
That's not to say that double-insulated and coded cords weren't in use on radios long before that. A lot of early 1950s sets gad it, with the standard red and black inner cores.
Even the twisted twins were coded sometimes, in that once you strip the insulation you'll see one wire has bare copper strands while the other is tinned to give them a silver appearance. The latter is the neutral, although you can't guarantee that somebody who didn't realize the code hasn't rewired the thing at some point and mixed them up.
Flat, 3-conductor zip-cord (kind of like a 3-wire version of American SPT1) was used on some radio equipment in the past. The center conductor was used as earth, and generally fitted with a green sleeve at the plug end to identify it, but the other two conductors were not always identified. I have an early 1960s Marconiphone phonograph wired that way.
On the modern BC pendant sets, I find that the round double-insulated cords take quite a time to straighten out properly after installation, unless they have a heavy fixture hanging on them.
