Complex sentence: Due to heavy drug references, the episode does not air in Channel 4 in Britain at all, and the only episode of "The Simpsons" to be banned from airing in Channel 4.
Split into simpler sentences: Due to heavy drug references, the episode does not air in Channel 4 in Britain at all. It's the only episode of "The Simpsons" to be banned from airing in Channel 4.