Sapphire And Steel was a barking mad, creepy and cerebral Saturday Teatime show that starred Joanna Lumley and David McCallum and seemed to always be set on darkened staircases or landings.
It was about...er, well, it was about...um....ok, here, this is a brief documentary about the show which'll explain it better than I can. Or not.
The inevitable Look-In strip by Angus P. Allen & Arthur Ranson is at least as creepy, weird and atmospheric as the show, plus it had better special effects. Here's Sapphire & Steel's first assignment.