King John's treasure is still very much a part of the cultural landscape in Norfolk. Anyone digging a hole for gardening or construction purposes runs the risk of some smartass coming along and asking whether he has found King John's treasure yet.

I saw a documentary some time ago that I can't find any more about some guys who raised money to look for King John's treasure with ground penetrating radar. They were unsuccessful but with more money and more recent technology there might be a startup opportunity in there somewhere. On the other hand, I can't imagine they'd be allowed to keep it.