Sapphire and Steel is the most eerie and atmospheric tv show I have seen in all my life. Always dealing with obscure entities, ancient enemies and time-rippings, they were the super-heroes ahead of their era.
"There is a corridor, and the corridor is Time. It surrounds all things and it passes through all things. You can't see it. Only sometimes, and it's dangerous. You cannot enter into Time, but sometimes... Time can try to enter into the Present. Break in. Burst through and take things. Take people." With this premise, P. J. Hammond wrote the first adventure of Sapphire and Steel and summoned a world full of odd situations, strange enemies, eerie atmospheres that was definitely ahead of his own Time.
I've never seen another show or movie that matches this show's sense of menace and doom that this has acquitted with only six adventures split into 34 episodes only 25 minutes long. Situations were as weird as a house that traps the parents of two children and stops all clocks, an abandoned train station invaded by the Darkness, a couple from the future experimenting in present era, a faceless man threatening people through photographs, an Agatha Christie set-up that Time brokes into changing events, and a hopeless group of people trapped in a Gas Station in the middle of nowhere.
Sapphire and Steel, a pair of agents from an unknown (and presumibably unearthly) organization, enter each episode trying to correct the anomalies and speaking each other in cryptic gibberish. That was indeed the most interesting aspect from this show: asisting to S&S's dilucidation of clues and facts gives the spectator a chilling sense of realism. The enemies were frequently hidden menaces and the solutions for each problem almost impossible to guess.
A feast of weirdness for the action and high-end fx tired viewer. Hard to imagine why this idea hasn't been rediscovered and remade for this century.