An electronics firm sets up shop in an old country mansion, only to discover that one chamber is haunted. Company manager Peter Brock (Michael Bryant) decides to use all of their cutting-edge equipment to record the ghostly visitations, but computer programmer Jill Greeley (Jane Asher), who seems to be the most psychically attuned person there, thinks that they are meddling in something that they should not.

I've read that this ranks among the most well-liked British TV fright films. I always enjoy when a story brings together the worlds of hard science and the supernatural, and Kneale, the noted creator of the Quatermass stories, is one of the best at it. This is no exception, and the film's title has become shorthand for a certain type of haunting in parapsychology circles. However, the movie loses a lot of appeal whenever it deviates from the main plot and tries to throw in some corporate maneuvering. I also wasn't crazy about most of the performances, which were often played too big and on the verge of hysteria. Lead actor Bryant seems to shout 90% of his dialogue for no good reason. Still, haunted house fans should probably give this one a watch if it comes there way.

A remarkably creepy and subtle evocation of dread, from a typically nuanced Nigel Kneale script. What if ghosts are simply phenomena that have simply been poorly described? That's just what a team of computer specialists, on the trail of a new recording medium, attempt to do when they discover that the old mansion in which they are conducting their work is haunted by the ghost of a victorian maid. Unfortunately, they discover too late that a rational explanation does not mean an end to the terror... TV drama as it should be done – sadly, we'll probably never see its ilk on British TV again. Still, at least those nice chaps at BFI have released it on DVD.

This was a very nicely executed concept of Nigel Kneale's.

Effects, directing and budgets had grown up a little since the cash-strapped days of Quatermass in the 1950's.

The premise was that if an event impacted upon the human psyche with sufficient vigour, a remanence of the emotional distress was recorded upon the physical fabric of the immediate world. As stone is usually much more resilient a substance than organic materials such as cloth or wood, the remanence would endure in it longest.

Of course, the story wasn't quite that simple. Sometimes there were overlays of imparted memory from different ages. Sometimes history not only repeated itself, but was induced to repetition by an earlier memory. The basis of all hauntings.

There were lots of subtle plays upon the idea, and likewise the susceptibility of individuals to detect or respond to these recordings. The question was posed; if nobody could see the ghost walk, would it actually walk?

Against this scenario, came a team of modern - what might be called boffins - attempting to develop a new type of recording medium. They stumbled upon the haunting and began to research a method by which it might be commercially exploited.

For the most part it was intelligently realised. The creepy borderline between human emotional frailty and the timelessness of its seeming persistence on the substance of the world, evolved in a suspenseful - if rather slow - revelation.

If I have a criticism of the drama, it is one of Nigel Kneale's in general. Characters were just too emotional at times. Conflicts seemed needlessly exaggerated, arguments and reactions too histrionic. There were occasions when I found myself muttering 'oh, for heavens sake, sit down and stop shouting', or 'why not just talk this over rationally'. As I say, this seemed to be a Kneale trademark, but I found the lack of a 'safe pair of hands' in most of his work tended to detract from the entertainment. But maybe that's just the way I was brought up.

If you get a chance to watch it by all means do. However, I saw it when first broadcast, and though I found the evolving conflict between science and supernatural extremely gripping, the strident characterisation rather irritated me even then.

If somebody hands me a copy, I'll give it a whizz. But for the most part hysteria just turns me off. It is too often used as a prop for a poor script.