“You see… This is the room.”

A young couple (Ronald Hines and Colette Wilde) arrive at Orchard Cottage, and before we can ask how much they like them apples, it turns out they like them very much thank-you.

“Well this can’t be it,” they comment. “You can’t buy a house like that for £2,500!”

You’re right, well-spoken chap (say I). Must be worth at least six. Even with the resident spooky woman who pops up to show them around.

The more they see, the more they like it. “There must be some sort of snag,” says the wife (that’s how she’s billed, shush). “It would have to be a big snag to put me off!” the young husband (same) replies.

Of course, there is a snag. Of sorts. “Perhaps it’s because of the ghosts…” their guide pontificates. And she starts to tell the story of the house.

So, we’re in a flashback, which involves a seemingly unconnected tale of a love triangle involving the cuckolded scientist Mark Lemming (Peter Dyneley). His best friend Clive (John Merivale) and wife Stella (Jane Hylton) are the source of much gossip in the locality until they disappear and Lemming is found dead in his workshop at the back of the house.

But, where does the ghost come in? Well, back in the present day, the spooky woman explains she’s coming to that.

And so starts a second story, about another young couple (Maurice Kaufmann and Nanette Newman) who also find and fall in love with the house. “At first things went well…” says the spooky woman. “But then things began to happen.”

The house appears to have electrical problems, and then the couple start seeing the ghostly vision of the same man (Lemmings) appear… not only around the house, but on the screen of their television (prompting a call – via the TV Times – straight to the ITV studio broadcasting at that moment to ask if they switched the scene to a moustachioed man. Which is brilliant in its stupidity, or maybe a real sign that 1960 was an utterly different time when doing something like that was a real possibility. They even get an answer (no) and a grumpy suggestion that they “must’ve switched to the BBC or something”).

This being unlikely, it’s time to bring in a psychic investigator to get to the bottom of things.

Now, to write much more would spoil for you what is a truly brilliant, and somewhat chilling, tale of murder, science and ghosts, which has echoes of later dramas The Stone Tape and Hammer House Of Horror.

House Of Mystery is that rare thing, an actual forgotten gem. Even its potentially annoying “flashbacks within flashbacks” don’t dent what is a smart little tale which spooks you right up to the predictable, but still effective, end.