I think you are all forgetting one legal detail. The Pope is a head of state.
Part of the strategy that the parties attempting to get the Pope arrested is to question whether or not that is the case, and thus whether or not he has diplomatic immunity. They claim that he is not the head of a nation state recognized by the United Nations. I have significant doubts at to whether or not they'll succeed, but we'll see.
The UK has recognized the Vatican City State since 1982. UN recognition is not required.
Like I said, I have significant doubts about their success.
Rest easy, Dibble, success is assured. If Cardinal X came here with diplomatic status, he'd be no different than any other official with diplomatic immunity. Can't touch him (pun intended).
