I’m (half-)British and I consider “could care less” a hideous American corruption. Recently I successfully argued my case with an American friend, not coincidentally a physicist, by analogy to zero-point energy.
I wouldn't call it a corruption though, because I've never actually heard it in Britain; just American film and television, and even on HN.
"Dear America..." https://www.youtube.com/watch?v=om7O0MFkmpw