That is a question that has puzzled people for quite a long time now, with so many pieces to it, and I'm sure will for a long time to come.
Did a young Jesus travel with his step-father (who was a tin merchant, not carpenter) to the tin mines in Britain and encounter Druids at Ynys Glas (Ynys=isle, Glas=blue, or glass...so we have "The Isle of Glass", as the area around the Tor used to be surronded by a shallow inland sea)?
Did Joseph hide the Grail in the Chalice Well?
How did that medeterainian thorn bush that blooms in the dead of winter really get planetd on the Tor?
Did Joseph really have the first Christian church on the Tor with permission from the Druids?
I don't think that there's enough evidence to fully support these theories, but I'm certainly not against the thought.
Name: Haman
Comments: I think the modern historian just wants to add the Jesus element in to give the Celtic druids more notoriety. Even if Jesus were to have met them he would have likely rebuked their practices.