There was a show on the history channel that I watched a while back that put the lie to the whole scam. On of the better parts was the discussion of English wine and how it was so much better than the French stuff that there were near wars over it. Then in the 1300s it got too cold to grow grapes in England and all was forgiven.
Here is the show's
DVD and a brief write up, don't know if they are going to rerun it, but it is worth watching. Chilling.
Do they grow grapes in England now?
No, the Vikings absconded with all the English vineyards and moved 'em to Vinland. Then one day it snowed, and all the inhabitants of Vinland were wiped out by a massive attack of migrating Polar Bears.