A cryptic advert has been cropping up in local news media over the past year.
It simply reads:
The nail will be kept in bag number 3. (And another bag will be knocked on the floor by a clumsy cow).
Which sounds like a coded message to a sleeper agent, doesn't it?
It appeared most recently in the Southend Echo this week, but has previously appeared in the Liverpool Echo, the Hull Daily Mail and the Newcastle Chronicle.
Adverts in the Southend Echo this week, the Newcastle Chronicle ten months ago, and the Daily Mail (Pictures: Imgur/Twitter)
The dates of the publication of the adverts appear to sync up with Derren Brown's preview tour dates for his stage show Miracle, and comments from Reddit and Facebook users claim it's actually part of his show.
The trick, reportedly revolves around Brown making someone predict which of a number of bags has a six-inch nail hidden inside it, by bursting the other bags with the palm of his hand.
We're not sure how the adverts come into it, but we guess that's part of the trick, isn't it?
Derren Brown's representatives have been contacted by indy100, we're not optimistic about receiving an explanation, however.