I don't think Thoreau actually hated Britain, Oct, I just emphasize that side of him to spite you.
A more accurate depicition of his feeling about foreign lands was that he had no need of them - to be content with wherever you find yourself was enough. He, incidentally, found himself in Concord, and was thus its proponent. But only because he loved all the Universe.
And, being American, he contrasted our way of life with Europe's to great effect.
Anyway, I know that there is public land in the UK, but not very much, right? Enclosure, etc? I thought one of the few exception in Europe was (I think) Sweden or Norway, where you have the right to camp on anyone's land without asking?