I misspoke. Napoleonic law presumes guilt. English common law presumes "innocence", but an Englishman has far fewer protections than an American under similar circumstances.
That makes sense; it seemed like that when I was there last fall.
I heard that it would still be technically legal for you to be arrested there, secretly tried by a military court, and then executed, without any right to outside counsel. I don't know whether this is still true, though.