Great cast, great performances, great direction...but the script...it was as if the writers either got bored of the whole thing or hastily finished it on deadline day.
An absorbing, at times very tense buildup, hints at something possibly occult going on, but then a rushed ending that didn't need the buildup! It begins with a kind of Rosemary's Baby feel to it but the plot and tension builds to a certain level then remains there at that pace for the rest of the film.
Well worth watching, but just enjoy the actors and mood and don't expect to be blown away by any clever plot twists and turns.
It should have been shown as a Sunday evening BBC2 play or something.