Stephen Volk's 1992 drama is hard to obtain on DVD. I've seen absurd prices quotes. Fortunately it's available to watch online if you don't mind risking eye strain. If you're too young or foreign (or both) the context is this. It was billed as a Hallowe'en visit to a genuine haunted house and the presenters - particularly Michael Parkinson - were seen as 'safe' or reassuring TV personalities who'd never been involved in drama or indeed hoaxes. The one exception was Craig Charles of Red Dwarf fame, but as you'll see he did his bumptious Scouser act to further allay viewer suspicion. That said, for a hoax show it played fair. You can see the writer credit for Volk in the opening titles, and the closing credits have a cast list. (Weirdly, there's also a credit for a Mike Chislett.) In addition to the 90 minute show below I've added a brief video showing the various sighting of 'Pipes', the genuinely disturbing spook.
A lot of people complained about the show, claiming it was too realistic and disturbing. Certainly a lot of people complained, but then a phone number was repeatedly put on screen as part of the 'mockumentary' format. According to Wikipedia:
Ghostwatch (...) currently holds the record for the highest rated single drama in the UK of all time with a peak audience of 11.5 million viewers, and an estimated 30,000 calls to the BBC switchboard in a single hour.