The true classic: A drama posing as reality TV to an unsuspecting audience. Prompted tens of thousands of complaints, which is always a good sign.
*cracks fingers* As Ghostwatch featured heavily in my MA dissertation, I'll point out that there was no "unsuspecting" about it: there was a cast list in the Radio Times that week, and there was a writer's credit at the start - and that's before the ultimate test, namely the BBC didn't immediately cut to a news broadcast saying that ghosts were overrunning the country, having possessed Michael Parkinson and apparently killed Sarah Greene That part of the story was cooked up by the following morning's tabloids
It's also worth pointing out that, if you called the number they show onscreen (which was the standard one for Crimewatch and Going Live), the operator would tell the caller that what was happening was not real In other words, the tabloids went off half cocked in spite of the evidence, which is totally out of character for them. Hmm, I wonder if, a few years later, any news broadcasters were similarly duped by The Blair Witch Project...?
That was quite good (a nod to the Enfield poltergeist incidents) . What was clever was having Parky involved, as it lowered the audience suspicion levels (Parky is a serious and respected TV presence, he doesn't get involved in silliness etc) .